So I'm writing this after seeing spoilers for the next Chicago Med episode - so if you haven't seen the spoilers then don't read this. Obviously I don't know exactly what is going to happen but I'm really disappointed that Jay does not seem to be in it, even when the character's brother's life is on the line. So of course, I had to rectify that. So this is loosly based on what I've seen but including some brotherly love and fluff for Christmas.

I have no medical knowledge whatsoever, so everything is totally made up to fit the story.

Hope it 's ok. Obviously I don't own anyone that you recognise - they belong to the Chicago Med/PD/Fire universe.

You Can't Leave

"You ok?" Detective Jay Halstead asked his older brother, who was currently nursing a beer, seemingly deep in thought.

"Huh?" Was all the red haired doctor could muster as he glanced up at the younger man. Jay could see the dark shadows under Will's eyes - they seemed darker than the last time he had seen him.

"I said are you ok?" he repeated, "You've been staring into the bottom of that glass for the last twenty minutes..."

"Oh, sorry...yes I'm fine," Will answered, without conviction, placing the glass on the table.

"You know, if you didn't want to come here tonight, you only had to say. We could've made it another night," Jay told him.

"No, it's fine. I wanted to spend some time with you - we don't see each other enough," Will argued looking at his brother. He pulled himself up straighter and took a deep breath, "To be honest Jay, I've not had the best of days. I'm exhausted as it is, which is normal I know, but today this young girl just collapsed in the department and within a few hours nearly all her body was paralysed - we ended up having to intubate her. They made me go home as I had already done nearly two full shifts but I can't help wondering..."

Jay reached over and patted his arm. He knew that his brother took his patients seriously, no matter what - so not knowing what had caused the young girls paralysis would lay a heavy burden on the doctor, "I'm sorry Will. I wish there was something I could do," he told him sincerely.

Will smiled a tired smile, "You're doing it. We're spending time together - it's good."

They settled into a companionable silence as they both drank their beer, both deciding at the same time that it was time to call it a night.

"I'm just going to the mens room," Will told his brother, who followed his every move, a frown etched on his forehead.

"Hey Jay, rough day?" Matt Casey from Firehouse 51 broke into his musings.

Jay looked to the fireman, who was taking a beer from Kelly Severide as he spoke, "Hey guys. No more than usual."

"So why the long face?" Kelly asked.

"My doctor brother Will, he's had a tough day and I'm just a bit concerned about him," Jay told them.

Kelly smiled, "I know that feeling," he said as he rolled his eyes towards Casey.

Suddenly, Christopher Herrman, who ran the bar, shouted Jay's name. Jay, Matt and Kelly all ran to him, skidding to a halt when they arrived at his position. He was holding onto Will tightly, as if the red haired man would fall over if he let go, "Herrman, what's going on?" Matt asked in confusion.

"I was walking in as Will here decided he was going to fall out of the men's room..."

Jay looked from Herrman to his brother, who slowly raised his head - fear etched across his features, "Jay, I can't feel my foot..."

Jay stood, stunned for a few seconds, "What do you mean?"

"I mean, I can't feel my left foot, which is why I almost nose dived into Herrman here - my right foot has pins and needles in it..."

The Halstead brother's eyes met - horror in one set and fear in the other, "You don't think..." Jay stuttered.

Will shrugged, "I don't know - but it's possible that she was contageous."

"RIght, we're going to Med - come on I'll get you to the car," Jay threw one of Will's arms around his shoulders while Herrman didn't let go of the other side. They all but dragged him into Jay's car and he sped off towards the hospital.

On arrival, Jay launched himself through the doors, almost knocking April down in the process, "Sorry April," he said.#

She smiled at his apology, "It's ok. But what's the rush?"

"I need a wheelchair...it's Will..."

Two minutes later, Will was being wheeled (all be it grudingly) into the familiar department. Maggie was the first to see them after April, " Will what's wrong?" she asked, shocked to see the popular doctor being wheeled in.

"Maggie, what happened to that patient that I saw earlier, the one with the paralysis?" Will enquired.

"She's been intubated - but she's holding her own. Why do you ask?"

"He can't feel his foot," Jay explained watching Maggie's reaction carefully.

"I can't feel my FEET," Will emphasised.

Jay swallowed hard. Maggie could see that Jay was struggling so took control.

"Ok get him into trauma two...Dr Choi, just the man - there is your patient - off you go."

Ethan's eyes widened as he took in the scene before him, then the doctor in him took over once more and so it began...

Within half a hour, Will had been seen by just about every doctor imaginable, but unfortunately, none of them could tell him why this was happening to him. Jay could see that his brother was becoming increasingly frustrated and tried his best to calm him down.

Natalie had been in to see him, but Will had sent her away, afraid for her if it turned out to be contageous. He had tried to send Jay away too, but his stubborn brother had refused, saying that if it was contageous then he would already be infected.

Presently, Ethan came back into the room and closed the door behind him. Jay was immediately on alert when he saw the young doctor's expression, "How are we doing Will?" he asked, trying to keep his tone light.

Will noticed immediately, "What's wrong Ethan?" he demanded.

Ethan looked to both Halstead brothers as he dragged in a deep breath, "I'm sorry Will, but the girl died about ten minutes ago..."

Both brothers glanced at each other. Jay couldn't contain his shock and fear, whereas Will looked resigned, as he let his head drop back onto the pillow.

"So have we got any results from Will's tests?" Jay asked, trying to stay on task while his body was reeling from the shock.

"We've nothing conclusive..." was all the younger doctor could offer.

Jay couldn't take that, "You telling me that in this day and age, with all the technology we have at our disposal, that you can't give us an answer?"

Ethan glanced at Will apologetically, "Yes I'm afraid I am at the moment. But you can rest assured that we are doing everything we can..."

"Well that worked for that poor girl," Jay spat.

"Jay..." Will tried to placate his brother, who looked disappointed that his brother wasn't backing him up, "I need some air!" And then he was gone.

Will sighed deeply, "I'm sorry Ethan, he gets like that sometimes."
"I don't blame him," Ethan said, "I feel exactly the same way."

"I know," Will breathed, "So what now?"

"Well as I told Jay, everyone is working flat out to find out what it is, but as I'm sure you know, if the paralysis carries on, your airway will become compromised which..."
"Could lead to heart failure. God how could this happen?" Will asked rhetorically.

Ethan shrugged, "Who knows. Wrong place, wrong time - your immune system could have been compromised by something else - could be any number of things. But I promise you we will fight this with everything we have," the younger doctor vowed as he laid a hand on Will's arm.

"I know you will Ethan. I trust you."

"Try to rest," Ethan advised him.

"I will if you would do me a favour?"

"Name it?"

"Will you go and find Jay - just make sure he's alright...please," Will's voice faltered.

"Of course I will - please just rest," Ethan said as he left the room and closed the door. He took a moment to watch his friend as he pulled the cover over himself a little more, then he let out a breath and turned away.

"You're doing everything you can," Maggie caught his eye.

"I just hope it's enough," he told her with a heavy heart.

Jay made his way back into his brother's room about half a hour after he had stormed out. Ethan had found him and talked him through possible scenarios and had also mentioned that Will had asked him to find the detective because he was worried about how he was coping. Jay had apologised to Ethan for his initial outburst, but the young doctor wouldn't hear of it. He assured the young man that he completely understood his feeling of helplessness.

The young detective pulled up a chair beside his brother's bed and just watched the red haired doctor as he slept. He looked so peaceful. No sign of whatever it was that was ravaging his body. Jay couldn't help himself as he took hold of the nearest hand.

"God Will, you certainly know how to cause a scene don't you?" he forced out, tryng to push down the emotions that were threatening to overflow.

"Got to keep you on your toes," he heard the soft whisper coming from the bed.

Jay chuckled, "Answer for everything," he told his brother.

"Jay," Will wanted his attention.

Jay stood so that Will could see him better, still holding his hand, "You're holding my hand?"

Jay held it up into his vision, clearly confused as to why Will was mentioning it, "I can't feel it," Will breathed out.

The lead weight that had lodged itself in Jay's stomach earlier began to creep up his throat, "Wh...what?"

"I can't feel your hand holding mine. I think you'd better get Ethan," he all but whispered.

Terrified, Jay managed to gently place his brother's hand back on the bed and went in search of Ethan who he found in the break room talking to Natalie.

"Ethan, thank god - Will's getting worse. He couldn't feel me holding his hand...it's getting worse really quickly - I..."

Ethan jumped to his feet as tears finally gathered in Jay's eyes and his hands began to shake. Natalie noticed this and guided the younger Halstead brother to a seat and poured him a coffee which he took with gratitude but found difficult to keep a hold of because his hands were shaking so much.

Natalie looked distraught too, "It seems to be moving quicker than we anticipated," she remarked.

Jay just nodded, not trusting himself to speak. Natalie placed a hand on his arm, which was Jay's undoing. Tears tracked down his cheeks unchecked as he struggled with what was happening, "I can't lose him Nat. For all we argue and fight, he's my big brother - I can't imagine a world without him in it...I just can't..."

Natalie put her arm around him and pulled him into a gentle embrace, "I know. Owen adores him and so do I so we can't imagine it either..."

The door opened and Ethan walked partially in, "Guys he is getting worse and we still don't really know what we're dealing with but I suggest that you go in there because I think we're going to have to intubate and I think seeing familiar faces will help him."

They both jumped to their feet, their fear forgotten for the time being - their sole purpose now was to get to the stricken man. Jay slowed to a walk as he neared the room as he didn't want to show Will that he was so freaked out. He closed the door behind him, mindful that Will didn't want Natalie to be in there with him in case she could catch whatever it was.

He noticed that his brother's eyes were closed so he gently touched his arm, but there was no response. Jay glanced at Ethan, who had followed him in, "He can't feel you..." was all the doctor told him.

Jay's heart clenched as his shaking hand reached up to smooth down his brother's unruly red hair, this time Will opened his eyes, "Hey," he whispered.

"Hey yourself. Trust you to be in such a rush..." Jay choked out, trying to lighten the mood.

Will tried to smile, " Nat?"

"She's outside. I literally had to close the door in her face. Not sure I'm her most favourite person at the moment."

Will smiled as he tried to take in a deep breath but ended up coughing so Ethan sat him up a bit. The stricken doctor moved his head round, smiling when he saw Natalie through the window. She smiled back through tears as she blew him a kiss.

"Jay..." Will whispered quietly so his brother had to lean down to hear him, "If the worst happens, please look after Nat for me..." he coughed slightly once more, "And look after yourself. You are an amazing person, and for all our fights and arguments...just know that I love you brother..."

His eyes closed as alarms all around him began to scream.

"Will, Will, come on don't do this to me, to us. It's Christmas next week, Owen will want you there to help him open his presents!" Jay begged as Ethan moved him out of the way and began to intubate. Jay wouldn't be moved however, and kept a firm grip on his brother's hand. The door flew open allowing an emotional Natalie access to the room and she headed straight for the other side of the bed and held on to the man she loved. She glanced over the bed to see the same fear she felt coursing through her body in the eyes of the young man opposite her. She tried to offer an encouraging smile as they settled in to their vigil...

So I've left it there as I don't know whether I'm going to do any more and if I do, do I let him go or will there be a Christmas miracle (all be it a little late).