Cas hasn't said anything for the entire car ride even after Dean picked him up off the soggy ground. He shook him hard, grabbing him at the soaked shoulders, trying to shake out of him what happened, what was going on, what this meant. Cas didn't even blink. He got Sam into the car first, then Cas, picking them up one at a time like children, his shaking voice murmuring reassuring words about how they'd "..fix it. We'll fix it, don't worry."
They ride through falling bodies of fire and black dust and Dean doesn't stop, he can't help them, there's nothing they can do. So he just grips the wheel and punches the pedal.
"It's alright, Sammy, just shut your eyes."
"Close your eyes, Cas, don't look at 'em."
"We'll fix it, we'll fix it."
He gets them in the bunker and tends to Sam who eventually stops shaking and sweating and passes out on the couch. All the while Cas stands by the door, eyes still wide and vacant. He's barely standing, just half-leaning against the door.
"Cas?"
"Cas, man you gotta talk to me." But he's so quiet it's like he's not even there, and his face is pale and washed out and broken. So he just says, "Come on, Cas.", tugs on his coat sleeve and leads him to his bedroom. And just like he has with Sam so many times, Dean grabs the former angel under the arms and throws his weak body on the plushy memory foam and yanks his wet shoes off. He just lays there, corpse-like and solid staring at the ceiling.
"You can, uh stay in here. Just rest, ok? I'm gonna be in there with, Sam. Make sure he's alright for the time being." After no response, he turns to leave Cas alone. What could he possibly do to make this okay? As he reaches the door, four raspy words creep their way across the room:
"It's all my fault." He barely hears him at first, it's just a mumble lost in his throat.
"...what?"
"Dean...it's...it is all my fault.", Cas's voice crumbles, pushed back by the unfamiliar lump catching in his throat.
"Cas, we'll fix it alright? Just-"
"It's my fault! I did this! It's my fault!"
"Listen, you gotta calm down. Just breathe." But he can't and then everything in him is spilling out of him, blinding him with salty tears, grabbing hold of his stomach and twisting. He's heaving and thrashing his body, digging his nails into the sheets, pulling and yanking and screaming because it's all he can do.
"IT'S ALL MY FAULT! I DID THIS! I DID IT! NO! I DID THIS!"
"Cas, stop! Calm down!", Dean screams at deaf ears.
"WHAT HAVE I DONE?! WHAT HAVE I DONE?!"
And suddenly Dean is on top of him, fighting hard to pin down thrashing arms. Cas lays a hard palm against Dean's chest, nearly knocking the wind out of him but he doesn't budge. He slams his knees down on Castiel's thighs, using all his weight to get him to stop moving, just for a moment. He wraps a tight fist around each wrist, slamming them down, knuckles scraping the headboard.
"Cas! Cas! Please, stop! Stop!"
"DEAN, WHAT HAVE I DONE?!"
"I'll fix it, I'll fix it," he almost whispers and without a second thought, leans down to plant a kiss along his hairline.
"IT'S MY FAULT!"
"Shhh."
And two on his neck.
"LOOK WHAT I'VE DONE!"
And three on his wet nose. And though Cas is still writhing and twisting he parks his lips against all the space he can, not missing a beat.
"Dean, I did this...Dean."
"Shhh, shhh."
Careful and easy he makes his way as far down as he can without letting go of Cas's wrists. He nudges the shirt collar out of the way with his nose to get to his clavicle, first the right side then the left, letting his lips drag over the sharp bone as light as a feather. The creep of Dean's nose across the base of his throat brings tiny, rough goosebumps to the surface. He feels Cas's body relax under him a bit, so he let's go of him with one hand to untie his tie and craftily unbutton the white shirt down to his navel. His lips stalk every inch, softly grazing chilled skin. Using his tongue only every now and again not just because he simply can't resist but because he wants so badly to make Castiel okay, to fix this. If he could, he'd cover every inch of him with this, this temporary bandage. And Cas is faintly sobbing into the pillow at his side, his body trembling and shaking at each breath. His ache fading but by no means gone. Dean let's go of the other arm now to move the shirt and coat out of the way to reach his ribcage. He nuzzles his head down under Cas's arm, and one by one kisses each rib on the left then the right. He digs his hands under his back, crawling his fingers up to the shoulder blades, where he guesses the wings would go, and massages, kneading the tips of his fingers into sweaty skin. Because that's what Cas needs. When he looks up at Cas's face after what seems an eternity, his eyes are closed, mouth open, tiny breaths making small pneumatic sounds against the pillow. And he's okay. Maybe not forever, maybe not for long, but Dean will find a permanent solution. But for now he is calm. For now, he is fixed.