Dean wonders sometimes why Castiel always seems to wind up broken.
Other times Dean knows. The nights he's downed too much whiskey to drive but not enough to pass out he remembers Castiel walking into that barn like a thing made of shadow and lightning, power wrapped in skin he wore like armor. Remembers Castiel before he'd found those faint little cracks running through that armor, before he just couldn't stop himself from driving a wedge in deep and prying those cracks open until what was left spattered red and wet all over a writer's living room.
There's no stable ground. It seems like barely a blink of an eye passes between Cas standing next to him strong and whole and happy (how rare is that?) to Cas spread beneath him on a hard bed in a drafty cabin, to Cas swearing as Dean traces his way down from scar to scar to scar. Dean doesn't let himself wonder how many of those scars he'd put there. All of them, really. Dean pushes that aside as he strips off layers until what's been hiding beneath the drugs and the sex is laid bare for the first time in years and Cas arches beneath him, Dean's name on his lips and his eyes wide.
And then there's this new hell now, Dean finding Castiel hiding in his dreams limp and wrung out like a shipwreck survivor who's just clawed his way to shore; he's dressed in hospital grays with that filthy coat of his wrapped around him like a shield, the one Dean saved all those months because as much he'd dreaded finding Cas again he'd known not finding him would always, always be worse. "It's quiet here," Cas murmurs, sighing as Dean turns him over. Not that he has to say anything - while Castiel's still never mastered the concept of personal space, or asking permission for that matter, deep down Dean's never really wanted him to. Dean traces his tongue around the edge of his lower lip before trailing his way down, leaving a line of soft, wet kisses that linger at the hollow of his throat, the curve of his collarbone, just over his heart. He works across Castiel's body until the trembling stops, until he can see flashes of the angel again and feels Cas' hands go tight in his hair. He whispers Dean low and rough and raw, the same way he had the first night Dean cracked that armor wide and climbed inside like he belonged there.
Castiel built him back up from nothing more than bones and dust once. Dean's more than willing to return the favor.