A/N Last part; same warnings apply.

Part 2 – Don

Confused, Don watched his brother more or less running away from him. Charlie had been talking to Megan and Colby. It was a normal scene in this office and Don hadn't thought twice about it until he had caught the shocked expression on his brother's face. As he went over, Charlie had hurried away.

So, he walked over to his desk, the most likely place for Charlie to see or read something to upset him. An innocent looking bag and a prescription bottle lay on top of it. Almost without conscious thought, he stretched out his hand and touched the bottle, verifying that it was real. He wasn't a world-class mathematician but even he could add one and one and come up with two.

He swirled around to face Megan. "You've told him?"

She threw up her hands in exasperation. "Don," she admonished while she stemmed her hands into her hips. "How were we supposed to know that you would even try to keep this from your family."

"I didn't keep this from my family," Don argued. "It simply doesn't concern them."

"What doesn't concern them?" Megan challenged. "That you were maybe exposed to some terrible diseases through the needle stick?"

Don took a deep breath and lowered his voice. "The point is maybe - why should I worry them if there isn't anything to worry about?"

Megan also calmed down. There was no use in a fight. "It is standard procedure. Charlie easily could have known or found out."

"But Charlie didn't know," Don countered and glared at Colby. "He didn't know until you've told him." He sat down in his chair and lowered his head until he could rest it in his hands.

"Sorry," Colby offered and clapped Don on his shoulder. "I just wanted to be nice and asked how you're doing."

Don raised his head. "And you couldn't have asked me?"

Colby snorted. "If tables were turned I wouldn't want to be asked. So I didn't ask." He gave Megan a pointed look and trotted to the break room with his cell in his hand, probably calling David to warn him.

Megan sat down next to Don who leaned back and rubbed over his face. "Charlie is a grown man. He doesn't need your protection."

"Charlie is a grown mathematician genius." Don sighed. "He doesn't deal well with probability in or below the single-digit range and health problems." He looked sideways to Megan. "You don't know how he was as mom got sick. Or when I was shot in a bank robbery case he had run some numbers for us. It was only a graze but for him it was enough to send him back to his P vs NP." At Megan's questioningly expression, he added, "It's an unsolvable math problem."

"Then go and talk to him." She pointed to the elevator. "We have your back here in case something comes up."

Don shook his head. "If I would know what to say to him, don't you think that I would have talked to him already?"

Megan leaned forward and patted his knee. "It doesn't matter anymore. Now it's only a question about not talking or saying anything. And we both know that saying something is far better than silence."

"Brother's keeper," Don grumbled. "I'll tell ya, brother's keeper. It's never going to stop." But he climbed back to his feet and headed to the elevator.

"Dad?" Don looked around the room, his sunglasses in his hand. "Anybody here?"

"Donnie?" Alan came down the stairs. "What are you doing? Is everything okay?"

Don paused but a look at his watch explained his father's strange reaction. It was early afternoon - neither lunchtime nor time to call it a day. "I'm looking for Charlie. Is he here?"

Now, Alan came to a halt and mustered his son. "What's going on?"

"Nothing." Don had the strange feeling he was sixteen again and having been caught trying to sneak in or out. "I just need to find him."

"To talk to him?" Alan asked with a frown on his face. "Because as Charlie was almost running out of here after he had spent hours on his computer, he looked like he needed his big brother."

"Dad." Don sighed. It had been the risk he had been willing to take. He had always known that if they found out it would be worse. Now he had to deal with the fallout. "He isn't here, got it. Do you know where he could have gone? He isn't at CalSci and he isn't answering his phone."

"Donnie, sometimes it would be better to talk beforehand and not afterwards." His father added his unhelpful advice while also secretly trying to interrogate him. Too bad that Don was used such tactics and didn't fall for it.

"Yeah, but what if I don't want to talk or there's nothing to talk about?"

Now it was Alan turn to sigh. "I can accept that you don't want to talk to me about something. But I guess Charlie hasn't shown this much restraint?"

Don snorted. "You know Charlie. And now I have to do some damage control." Rubbing at his neck, Don knew that he was supposed to talk to his father but somehow the words stuck in his throat. So many thoughts were circling around his head and he hadn't had the patience trying to sort through them.

"No way but through it, right?"

Startled, Don looked to his father. He needed a moment to register the words. "Yes."

"And for you there's no use to talk about it? I guess I need to live with that." Alan walked the short distance to the table and put down the laundry basket. "But Charlie has found out, right?"

Don nodded. He pointed to the basket. "What's that?"

Laughing without humor in his voice, his Dad crossed his arms. "That is me doing the things the house owner should be doing."

A small smile tugged at his lips. Charlie and Dad arguing about chores were a normal, a safe thing to talk about.

"He said that he needed to clear his head but you wouldn't forgive him if he went to his numbers." Alan indicated the door with his chin. "So he took his boots and headed out. I guess he is hiking."

"Thank you," Don said and patted his father on the shoulder. "Thank you," he repeated, "not only for taking care of Charlie but also for ... you know."

"Not asking? Believe me, I worry about you, but I also trust you. You will come to me when the time is right for you, not for me."

"I'll tell you. I promise, I'm going to-" Don pleaded with his eyes for understanding. Some things he couldn't put in words and other things were better left alone.

"Go and talk to your brother. I'll be here waiting for you. For you both."

After talking with his father, it was easy to track down Charlie. There were only a few routes he could take with the remaining daylight. So, Don only had to canvass the possible parking lots.

The sun was already going down as he finally spotted Charlie's car. Slowly he parked his car beside it and turned off the motor. He wasn't ready for a conversation with Charlie. He simply wasn't ready or prepared but Megan was right. It wasn't about knowing what to say, it was about keeping silent or talking.

Life had been easier before he had returned to Los Angeles. Nikki, Terry and Kim, they all would have understood what this meant and accepted that there wasn't anything to talk about it. Just like Colby, and just like the rest of his team had understood. But not his family, especially not Charlie, could deal with it like that.

Don jumped out of the car and leaned against the warm hood. For a short moment, Don closed his eyes and let the sun warm his face.

He listened to the nearing steps until they suddenly stopped. Waiting for them to start again, Don balled his hands into fists. He wasn't here for a fight, but he also wasn't qualified for this talk or to deal with Charlie. There was a reason he had avoided it.

"Did you track me down through my cell phone? Or credit card or my car?" Charlie sounded weary and suspicious, but mostly shocked and angry.

Taking a deep breath, Don opened his eyes. He found Charlie waiting next to his car. "Neither." He pushed away from the hood, stepped towards the blue car and put his hands on top of it.

"Really?" Charlie accepted the barrier between them. The car was a small obstacle compared to the real problem.

Don shrugged. "I'd wanted, but Megan advised against it." He stared at his brother and noted the nervous energy around him.

"So?"

"So I used good old police work and asked Dad."

Charlie laughed out loud. "Dad." Playing with the keys in his hand, Charlie appeared to be one step away from getting into his car and driving away. "Did you tell him?"

A snappish question in return was on the tip of his tongue, but Don swallowed the words before they could leave his mouth. He knew what Charlie was talking about. "No."

At the unexpected truth, he deflated and looked down. The nervous energy was replaced by tiredness and hanging shoulders. "Why did you hide this? A post-exposure prophylaxis?"

"It doesn't concern you," Don said.

With a flash, the anger was back and Charlie glared at him. "You're my brother."

"Exactly," Don shot back before Charlie could continue. "And I learned the hard way what you can and cannot deal with - and you and sickness don't get along really well. Or have you forgotten Mom?" It was a low blow but as far as Don was concerned it was the truth.

Charlie looked like a kicked puppy. "I'm dealing ... It's not like as mom got sick."

"I hope not because I can't do both, staying sane and worrying about you." Don pushed away from the car. He wasn't feeling well and emotional loaded conversations didn't help.

His brother circled around the hood of the car until he stood opposite to Don. "Why didn't you tell us? Tell me? I thought you would come to us with something like this."

It would always come down to this question. "Charlie," Don started, "you don't do well with waiting and not knowing."

"I do," Charlie argued.

Don smirked. "Didn't Dad tell you something like: wait and see? He sure seemed to have this impression."

Charlie crossed his arms. At Don's raised eyebrows, he shrugged. It was a sign of conceding.

"And who went to my office trying to find out what's going on? Thinking and searching over any and all clues?" Don had to work hard to keep his anger at bay. "This isn't waiting and seeing."

"Fine." Charlie threw up his arms. "I know. But I can deal better with knowing. The more information I have the better I deal. You have to give me some information."

"Charlie," Don sighed. "I don't know more than you already do. The docs gave me the standard numbers of probability and a phone number for counseling." He laughed but there was no humor in his demeanor. "You have probably calculated the numbers yourself." Don fell silent.

"And?" Charlie prompted.

"And nothing. It's all there is. I can only take the stuff - even if it makes me sick - and wait. If in six months the HIV antibody test still is negative, the needle either had been clean or the stuff worked."

"What about other diseases? Like hepatitis? Are you vaccinated?"

Don frowned. He had been right. Charlie was already a walking encyclopedia about needle sticks and risk associated with exposure. "The same - wait and see. There isn't anything to be done except waiting and treating any infection."

Suddenly new steps neared the location and two tired but content hikers arrived. They stopped as they saw them. Don forced himself to smile reassuringly. He could image how his discussion with his brother had to look for others and hoped to stall any questions. After a few moments, the hikers relaxed and went to their car.

By an unvoiced agreement, Don and Charlie waited until the red Chrysler was leaving the parking lot. Don leaned against his black SUV and Charlie rested his back against his own car. There was still enough space between them.

"Are you afraid?"

Don's head snapped around, away from watching the taillights of the leaving car, to his brother. "What?"

"Are you afraid?" His brother repeated stubbornly the question as if Don hadn't heard it and not as if he had been shocked.

"Of course."

Charlie let his arms fall to his sides. "But you don't show it. You hide it. You go to work as if nothing happened and you're keeping this away from us."

Don looked away to the forest line before he settled on the last damaging response. "People depend on me. I have responsibilities."

"To me," Charlie wasn't the best person for interpersonal communication but he was also his brother and they knew a lot about each other.

His eyes flickered to his brother. "Of course. And to Dad, my team and a lot of other people. I can't just fall apart just because I was nicked by a needle. There's no use in worrying now." Sometimes Don didn't know if he tried to reassure himself or others.

"You know, I am not only afraid. No, I'm terrified that I'm going to lose you like I lost Mom - slowly and painfully."

Don's gaze returned to safety of the forest line. The shadows were now almost upon them. The dusk had arrived.

There was nothing else to add to this. In the dark of the night and his dreams, he feared the same. But now It was Don's turn to change the topic, steering it to safer grounds. "I guess we both don't deal well with the loss of control."

Charlie furrowed his eyebrows. "What do you mean?"

Don smiled a little. "I'm fine as long as I am in control."

"I prefer information," his brother said and nodded to himself. "I don't need control, just some information to calculate the probability for different outcomes."

"It's the same Charlie, you need information to make better decisions - and making decisions is a form of control. Or you use the information to calm down yourself."

The silence stretched again while it got darker.

"You know," Don said as his brother continued to brood. "It's like the Charm School Boys. I was able to confront them again despite your helpful calculation about the probability that I would survive."

Charlie raised his head. "I haven't meant it like that, and you know that."

"My point is," Don talked over Charlie's protests now that he had his attention again. "I had control. I knew my team, I knew the layout - I had a plan. I could control the situation."

Understanding dawned on Charlie's face about what Don had wanted to say, or maybe it was too dark to interpret his expression correctly. "But I didn't and so I returned to the one thing I could control - my numbers."

"You told me that you couldn't control what you're working on."

"That's true but with numbers I'm always in control, it doesn't matter what I work on." Charlie slowed down. He looked away as realization sat in. "But here isn't anything I could calculate. There is no algorithm to enter in the supercomputer. The stick has happened and nothing is going to change that. It's like waiting for the dice to fall," he whispered.

The darkness was now almost palpable in the air and the first insects of the night started their concerto.

"It's even worse than with mom." Charlie's voice was even quieter and Don had to lean forward to understand him. "With mom there was opportunities and therapies. We - I could do something."

"Until the end where you couldn't."

A small sob escaped Charlie's lips and he nodded. "Yes." At this point the safety of his numbers had won and lured Charlie into the garage. Somehow they always ended with Mom whenever they tried to have a real conversation. Maybe she had been the only one to force them to talk.

Don pushed fully away from his car and took a step forward. Without touching his brother, he selected his new resting spot and leaned against Charlie's car, next to his brother. In the dusk, Don couldn't see clearly Charlie's expression anyway, but he could feel his presence and emotions.

Maybe it was time to explain Charlie a few things, he had learned. It was easier to start talking under the cover of the nearing darkness. "I guess this is the bad side of being brilliant."

"What?" Charlie turned slightly towards him.

"You have never hit the invisible wall in normal life, have you?" Don kept his head forward and watched how his dark SUV blurred with the wood.

"What wall?"

"For normal people there's a wall - a wall you can see through but never get through. Behind, there's all the knowledge people around you have but you can never hope to understand." Don knew his explanation wasn't perfect but it was the best he got.

"There's no such wall." Charlie shook his head.

Don breathed deeply. There was no use in getting impatient just yet. "Charlie, I hit that wall long time ago when I realized that I couldn't follow my little brother anymore. That you were talking about things I didn't understand."

"I often encounter things I don't understand. But then you just have to learn it. It's not -" Charlie opened his hands as if he could grab all the knowledge of the whole universe.

"Charlie, there is such a wall," Don repeated. "It's encountering the one thing that you can't learn. I'm good with three dimensions. I can imagine time and place, but with the fourth or fifth dimension my ability to follow you diminish until I can't even understand what you want to tell me ... for me there's a limit to my ability to expand my knowledge."

Stubbornly Charlie shook his head again. "Then I don't think I've ever hit your invisible wall."

Now Don smirked. With a few extra rounds, he had his brother where he had wanted him. "But you did - you hit it as Mom told us there wasn't any other therapy left to try. And you hit it again as the Charm School Boys left your predicted pattern. And now you've hit it again."

"But this is predicting the future and cannot be done, this isn't about learning." Annoyance and a good deal of anger radiated off Charlie.

But Don wasn't backing down. "For me it's the same. I don't care if I don't know something because I can't learn it or because it's not predictable. But I have learned to deal with this a long time ago." Don tried to see his brother out of the corner of his eyes. "I can deal with my inability to know everything. Nobody has ever expected me to know everything. But you never had to learn or to practice this skill."

"The sky is the limit," Charlie agreed.

"But death keeps you chained to the ground."

With the darkness the air chilled down, but they didn't move. Too precious was the time they spent together, and too precious was their one shot at this important conversation. Neither would dare a second attempt. And so they let the silence stretch until they had sorted through their thoughts again.

"And how do you deal with it? With hitting your invisible wall?"

"Like always." Don snorted. "I pretend to know the answer."

"What?"

Don turned his head to his brother. "I cannot know if the needle had been clean, but I can pretend that nothing has happened and I'm just taking these pills to keep the doc happy."

"And that works?" Charlie asked and the incredulity echoed in his words.

"No, not really," Don confessed. "But it keeps me busy. It's not easy to pretend but it's easier than to endure the not-knowing."

The darkness had now fully engulfed them and Don could only see the silhouette of his brother. His index finger was tipping against his chin as if he was thinking. Above them the first stars started to be visible.

"And if this doesn't help?"

Don shrugged. "I guess then I have to go the temple and ask a rabbi."

He felt his brother's confusion. "Why?"

"To get an answer, you need to ask the right questions. But you also need to ask the right people. If I ask a technician about the autopsy report, I'm not going to get very far. And if I ask Megan about the inner workings of a military unit I could also read a book." Don glanced sideways to see if Charlie was at least still listing. "So, if I need an answer to the question about life and death, morality and mortality or meaning of life I can't ask a physician or mathematician. I can only go back to the roots of our people and their ways to answer these questions, distilled through the centuries."

Don patted Charlie on his shoulder. "But don't worry. For now, I'm good with pretending everything is fine. Just ask my team."

Charlie nodded. "I guess -"

Suddenly Don's cell shrilled its alarm. Both startled but Don recovered first and shut it down.

"And now?"

"Now I'm done being the responsible old brother and tell you for the last time - it doesn't concern you and I don't want to talk about it, got it?"

"You don't want to talk about it because it hinders your ability to pretend it's not something to fear."

Don threw his hands in the air. "Finally." He thumbed his remote to his car and opened the door. The indoor light brightened the surrounding area.

"Hey, I'm brilliant. It takes some effort to understand normal people."

"Careful, Chuck, careful," Don warned. "I'm still stronger."

His brother smiled and the worry lines around his eyes disappeared. "Yes." But then his smile dimmed again. "But you're going to tell me your results, right?" He swallowed hard, the fear lurking behind his brave mask.

Don looked across the parking lot to the lights of the city. "No." Then he looked back to his brother. "But I'm going to tell you if there's something to tell you."

Relived, Charlie grinned. "Fine. But then I retain the right to ask you."

"Fine. But don't be surprised if I don't answer."

"Fine."

For a moment they remained. Nobody wanted to destroy the slight peace agreement they had signed without paper or pen. But then Don broke the spell and jumped into his SUV. "I need to get back. Are you coming?"

Charlie sighed. "No. I'm going to stay a bit longer."

"Okay." It was dark, but Charlie was a grown man. He knew not to go hiking or wandering off in the dark.

"Don?" Charlie asked.

He stopped, one hand on the door handle and the other over the key in the ignition. "Yes?"

"Are you coming over again? We could watch a game. No food is necessary."

With a smile, Don started the engine. "Sure," he said above the noise. "I'll be there." Don reversed out of the parking space. In the light of his headlights, Charlie smiled again.

The End

A/N Thank you for reading.

07/02/2018 Minor grammar and spelling corrections.