Sam leans against the wall of the church (so dark now, after the bright light of archangels arriving and leaving) and tries to wrap his mind around what just happened. On the one hand, Lucifer is dead. Loose-limbed, burned-out, charcoal-winged dead. Gone. On the other hand. No, don't think about the other hand. One hand is all he can deal with right now.
He doesn't realize Jack is standing right in front of him until he feels the tentative touch on his arm, and even then he can barely see him through the afterimage of Lucifer's fiery death, burned into his vision.
(It's so dark in here now. All the light left when Dean did.)
"Sam?" Jack's voice is tentative. Frightened. "What do we do now?"
Sam pushes himself off the wall and kneels at Lucifer's feet, and oh, that's a familiar act, and his lizard brain screams at him to go all the way down, to press his forehead against the floor, to feel the cold seep into his bones while he awaits his punishment. But this isn't Lucifer any longer. The dead man in front of him is just another one of the Devil's victims. A wedding band gleams dully on his finger, and Sam wonders, as he often has, about those who were left behind when this man agreed to be Lucifer's vessel.
(Sometimes people just get left behind, and there's nothing you can do about it.)
"What we do now," he says, "is give this guy a hunter's funeral."
"Like you did for Castiel."
"Yes, exactly. Like we did for Cas."
"But Castiel came back. Does that mean... could Lucifer come back?"
Sam hesitantly reaches out and touches the dead man's hand. It's cold, of course. It hasn't been human-warm since Lucifer slid inside it.
(Just another one of the Devil's victims. Someone who never would have crossed paths with him if Sam hadn't released him from the cage. So. Just another one of Sam's victims.)
"I don't think there's anything we can do to prevent Lucifer from coming back. But we can put this man to rest. We can do that for him."
Sam gets up with a pained groan, feeling bruised and battered inside and out. I'm getting too old for this shit, he thinks, and suddenly he misses Dean with such an intense ache that he almost collapses, sobbing, in the ruins of Lucifer's wings.
Instead he looks at Jack and says "And then we've got work to do."
(I know this isn't Nick's original body, but Sam doesn't know that.
The title is from 'Once in a Lifetime' by the Talking Heads.)