A/N: Set after s10e09: The Things We Left Behind, written before the air of s10e10.

"Hey, Cas, you still with us?" Dean's eyes should probably be on the road, but they're glued to the rearview mirror where he sees Cas tilting himself up, trying his damnedest to look like he hadn't just nodded off - like the stolen grace isn't starting to really fade, slowly taking him with it.

"Yes, I...yes?" Cas looks hopelessly disoriented. Dean wonders if he even remembers what they're doing, where they're going.

"Hey, you need to sleep, you need to sleep," Dean says. "Don't like it anymore than you do. Trust me. But acting like you're okay isn't going to help. Take it from someone who knows."

Cas sighs, looking a little defeated. "I am rather tired."

"So sleep," Dean says. "We'll wake you up before you turn into Rip Van Winkle. Promise."

"We'll find you a blanket too, when we stop. I know you kept getting cold, uh...you know, before..." Sam trails off, looking a little guilty.

Cas, unphased, thanks them both genuinely before curling up against the passenger side window, using his balled up trenchcoat as a pillow.

As he seems to drop off, Dean turns to Sam. "How bad was he, you know, before?"

Sam glances back at Cas, checking that he's really out. Once he's sure he is, Sam's expression turns serious. "Bad. He was bad."

When Sam doesn't elaborate, Dean rolls his eyes. "That's specific."

"Okay, so, he was sleeping a lot, even for a human. He started coughing, I don't know, half the time we talked. He was slow, weak. I didn't really want him looking for you with me, because it was, well, I think it was kind of killing him."

"Yeah, and it's killing him again now," Dean scrubs at his face as he looks back at Cas curled against the window, shivering slightly as he dozes. He'd do anything to not have to watch him slowly fade away like this.

"We've got to fix this. Him," Dean says.

Sam frowns contemplatively before hedging. "Not that I don't agree with you, I mean it's Cas, but how? We don't know what Metatron did with his grace. And I think Cas was kinda pissed at Crowley about whoever's grace he has now."

"Yeah, because it's a bandaid on a bullet hole," Dean says.

"Yeah, there's that, I guess," Sam says. "But the other, bigger thing, for Cas, I think, is that Crowley killed another angel for it."

"Yeah, so?" Dean says. "Now there's one less dick in the world."

"Pretty sure that's not how Cas feels about it," Sam says.

"Right."

Dean knows, obviously knows, that Cas is an angel. But the thing is, he can't put Cas in a group with the rest of them. Sure, Cas has, on occasion, been every bit as dickish, but Dean can't help thinking that that's not Cas. Not now, not anymore.

And so, if running off the mojo of those other dicks, who are still actually dicks, is what's going to keep Cas going, Dean doesn't think it's the worst thing.

He knows it's not what Cas wants. Hell, it's not really what he wants either. It's just stalling the inevitable fizzling out at the end of the sparkler.

But, because Metatron is a total douche, Cas' way, of getting back his own juice, is next to impossible.

And, because there's no way in hell it's what Cas wants, or that Dean's even going to suggest it, Dean's not getting his way either. Not that it matters, really, since the way he's going, he's not going to last all that much longer himself.

So, he and Sam, knowing they've got nothing, wordlessly drop the subject and focus on the road ahead - the road to Cain's.

Sam, mercifully, doesn't ask Dean how he's doing; the answer isn't something he wants to share.

XXX

It's hours later, when they've covered half the distance between Sioux Falls, where they've left Claire with Jody, and Saratoga Springs, where there's rumored to be a reclusive beekeeper, when Cas startles awake with a coughing fit violent enough that Dean stops the car just to make sure he's okay.

Once Cas assures him, many times, that he really is, that the grace is only just starting to burn out, that there's no need to worry, not yet, Dean decides to take matters into his own hands in the only way he can think of.

He pulls into the next Gas N' Sip and scarfs down three hot dogs, for his own sake, before grabbing orange juice and half the stuff in the cold and flu aisle.

So what if Cas isn't human and doesn't have the flu? It's not like it's going to make him worse.

"Cheers," Dean says as he taps his bottle of Coke against Cas' two teaspoons of cherry cough syrup.

Cas grimaces as he swallows. "I hope this helps, Dean. This tastes terrible."

"Doesn't everything taste terrible to you?" Sam calls from the trunk.

"It's not just the molecules," Cas says.

"Could have been worse though. They had grape," Dean says.

"Don't listen to him, Cas. Cherry is definitely worse," Sam makes a face as he tosses the blanket he's finally managed to unearth into the backseat. "Dean, you want me to take over? You've been driving for like ten hours. If we're not stopping, you should get some sleep."

"Yeah, okay. Think I'll sleep back here," Dean says before he realizes that both Sam and Cas are going to think that's a strange decision. Because it is. It's just that he's worried about Cas. And worrying about Cas is a good way to not worry about himself. "Cas can share that blanket."

Sam kind of side eyes him over it but doesn't actually question him before taking the keys. "Suit yourself."

Cas squints a little before spreading the blanket over their legs. They both pass out for the next six hours.

XXX

Cain's not in Saratoga Springs, and, Berchtold, the reclusive beekeeper they do find, reroutes them to Flagstaff. Dean jabs his hand against the steering wheel, wincing as salt leftover from his fries gets on the dashboard. "The frigging other side of the frigging country."

"It's still a lead," Sam says, giving him his best hopefully apologetic look.

"Yeah, whatever. Get in. We're burning daylight or something," Dean says as he waves Sam and Cas into the car.

They make a slight detour to the bunker, as Sam and Dean, through a lot of silent gesturing, agree to tell Cas that Sam thinks there's some lore in the library that might help them with reaching out to Cain.

It's really a ruse to try and get Cas to stay in one of the bunker's unused rooms.

Once Cas catches on, he is very stubbornly insistent not only that he is, of course, coming with them, regardless of how he feels, but also that the human remedies Dean's been slipping him every couple hours for the past couple days have been helping him significantly.

And it's odd, because Dean and Sam can both tell when Cas is outright lying; he's really, exceptionally terrible at it. So they know he's not by how sincerely he says he feels better. But he looks so much worse than when they left Pontiac; he's at least two shades paler and just seems ragged around the edges.

"You sure, Cas? You look like hell," Dean says.

Cas sighs. "The human remedies...they make me feel...more like a sick human than..." a dying angel remains unspoken, "but I can still feel the grace thinning. So... I think I feel both more... more and less. But I know that I will feel better if I stay with you. I want...I want for you to be okay. I like knowing it."

"And I want you to be okay too, Cas," Dean says.

"I suppose we are two peas in a pod," Cas says.

XXX

Before they get back on the road, Sam corners Dean in the kitchen. "I think Cas is... not lying, exactly, but... you know something about this doesn't add up."

"Well, his funeral, if he is," Dean says. Which is, more or less, what he's worried about.

Because while Cas may not be outright lying, because that's not what he does, he could be - and, god, Dean hopes he isn't - holding something back.

And if he is, he's gambling with, at the very least, his own life.

It's not something Dean really wants to consider.

He's had enough of Cas' lies of omission to last five lifetimes.

"Dean," Sam says, "the grace he had before took months to start going out like this."

"So? Maybe different angel batteries come with different warranties? I don't know, Sam," Dean says. "But what could he possibly be doing with it that we wouldn't know about? Not like he's zapping off on his own right now. He can barely walk a mile. And, hell, he's been with us for the past three weeks."

Sam purses his lips. Dean's certain he's not going to like where this is going.

"Spit it out, Sam," Dean demands. "What do you think he's doing?"

Sam sighs. "Trying to heal the Mark."

And Dean's immediately pulling up his sleeve, staring at the darkened skin he wishes he could just rip off his arm.

It doesn't look any different.

"Kind of think I'd notice him pumping me up with angel juice," Dean says.

Cas brushes past them, reaches into the refrigerator for the last bottle of orange juice, and sighs wearily. "You're a very sound sleeper, and Sam is a rather conscientious driver."

After that, Dean doesn't speak to him for the rest of the day - which is particularly awkward as the three of them are crowded into the Impala for most of it.

Dean doesn't care. He's pissed.

He doesn't have to ask why Cas didn't tell him. Cas didn't tell him because he never would have let Cas try to do this.

Because it's a goddamn death sentence.

And for what?

Nothing.

Absolutely nothing.

It's not like the grace that's apparently floating around his bloodstream is dwindling his maddening urge to kill anymore than the three burritos he just polished off.

Except, the thing is... he thinks, maybe, it kind of is.

He doesn't feel a hundred percent - though, truth be told, he doesn't know when he's ever felt a hundred percent. But he doesn't feel at all like he did in Pontiac.

Before, he'd been forcing himself to eat, trying to feed the insatiable bloodlust of the Mark with cholesterol, but for the past couple days, he's felt something closer to real human hunger - actually craving the things that had, for the past several months, become next to tasteless.

So now he thinks he feels both more and less.

He knows someone who can relate, but he's not quite ready to give up the cold shoulder.

XXX

It's nearly two a.m. and Dean's fast asleep in the passenger seat when Cas shakes at his shoulder urgently.

Dean's not awake enough to remember he's pissed about anything other than being dragged out of a dead sleep. "What, Cas?"

"I think...I think I need to urinate," Cas says stiffly.

And Dean's also not awake enough to get the implications of this. He scrubs at his face. "So tell Sam to pull over. What did you wake me up for?"

"Dean," Cas says, impatience and anxiety bleeding into his name. And Dean shoots up, eyes wide open. Because that's not something Cas should need to do, not in his current state of being.

"Oh. Oh shit," Dean says. "What does that even mean?"

"I am not certain," Cas says.

"Okay. Okay. We'll figure it out," Dean says. "But, you ain't going in my baby. Sammy, pull over. Cas has to pee."

"We'll figure it out?" Cas repeats skeptically. "But aren't you...aren't you still upset with me?"

Dean snorts. "I'm going to be mad at you for a long ass time. You got to stop pulling shit like this and actually tell us what you're doing. But, dude, that doesn't mean I'm going to stop taking care of you. That's what family does."