The first time they touch, he’s trying to help.
Sam is hollow, he’s empty, and while he’s approaching the situation with some pragmatism, Castiel can’t stand the desolate look that crosses Dean’s face whenever his brother’s not looking.
There’s no cure for the loss of one’s soul. Or rather, there are two cures, but one of them is “get the soul back,” which obviously they’re working on and which might not be viable anyway, and the other one is—unthinkable. At least by Winchester standards, which Castiel is still getting a grip on. (They are, in their own way, both as strict as the Commandments and as malleable as clay.)
The soul, Castiel thinks, is a spark. A source of warmth, the fire of compassion and admiration and empathy and love. A mundane fire can be relit; can this one? Can a soul be rebuilt?
He thinks not.
He comes when called and when he sees that it’s only Sam, sleepless as always and staring out the window of a cheap hotel suite, he assumes the worst but still says, “Sam. What did you need from me?”
“I’ve lost my shadow, Cas.” Sam stares out the window. Dean snores in the next room. “And I can’t get it to stick back on with soap.”
Castiel’s host once had a wife, and a child who loved bedtime stories. “Unfortunately I don’t think sewing it back on would help either.”
“I guess not.”
But pins, maybe it can be pinned back into his chest like a butterfly on a card, maybe proximity to Castiel’s holy fire will relight the fire that has been stolen. Maybe, to be crude, Castiel can fuck the soul back into him—or at least, that’s Sam’s logic. Castiel finds it ludicrous but difficult to argue with.
“I’ve never done this with an angel before,” Sam says to him, sounding pleased.
“I am not an item on a checklist, Sam.” Castiel clears his throat awkwardly. “I’ve never done this at all, it’s not something angels typically do.”
Sam is hot inside, so hot, but nonetheless Castiel cannot light that fire. There is no healing to be done. And yet—it feels good. Not right, necessarily, but good at least.
Perhaps it’s a slow process, Sam suggests, rebuilding a soul?
He stays until they hear Dean waking and then is gone, leaving Sam alone with his brother.
It’s an occasional thing, for help or solace or simply contact, and then for several years it’s nothing at all. Castiel tries to be impassive, but finds that he misses it when they fall out of the habit of…touching.
Which is not a rare commodity, he can get it elsewhere. Affection—perhaps that is.
Despair is still a cardinal sin, it signifies a loss of faith, but Castiel feels justified in indulging himself once in a while. But now—
Sam says, “You look grim.”
Castiel stares up at the loveless sky. “I seem to have lost my shadow, Sam. And I can’t stick it back on with soap.”
Sam leans against his shoulder. “I’d offer to sew it back on for you, but I don’t think I’d do a very good job. I can’t do much more than darn socks.” Seated and leaning, he’s almost not taller, and the gunpowder smell in his hair is calmingly familiar.
“It seems like a great deal has happened since you first said that to me.”
“Eh.” Sam shrugs. “Got my shadow back, and it’s only the end of the world again. We have to make our own fun, right?”