Sam didn't stir right away, though the lack of a body to curl against got him to wake a moment, blinking blearily and confused around the room--wouldn't be surprised if he'd just dreamed it, really.

He saw Dean moving to slip under the bed though. "You going to bed now?" Was it already dawn? He should probably get up, look up cases or try to figure out their next move with dad but... instead, he was huddling under the covers again, eyes drifting shut again. Five more minute, then he'd get up. Let Dean get nice and settled in first.