Dean can feel John's glare burning a hole in his back even as he's setting Sam straight (or thinks he can, at least; if he could see he'd know John isn't glaring, isn't even looking but has pointedly found something else to watch – it's exactly what Mary would have wanted, the boys looking out for each other, Dean taking care of his baby brother. John, for his part, is torn on whether it's the best thing or really bad news, and adds that to the list of things he hates about the decisions that got made for him by something he hasn't managed to track down and kill yet) and is quick to sound the retreat back to his corner though he'd rather be within arm's reach because Sam still looks like a strong gust of wind will knock him over and shatter him into brittle shards.
John takes Dean's place, and for all the world looks like a drill sergeant inspecting a recruit, the way he runs his eyes over his son, pats down his shoulders as if straightening him out. The brief, fierce hug which follows the inspection doesn't really fall within the bounds of those regulations, but it's the easiest way to say Sam passed whatever standard qualifies as acceptable, as 'okay', and far easier than actually coming out with I'm glad you're alright, son.
He pulls back before Sam can ask what the hell that's for, before it turns into something it's not and raises old ghosts of men he wanted to be but isn't, the suits he thought he'd grow into with time (this one 'father', this one 'husband') but are now shoved in some closet in a house that burned down. Dean gets a nod as he pulls his armour back on, retreats behind the walls of Fort Winchester. “You've got ten minutes, Sam. Dean, help me load the car.”
Dean, of course knows better than to argue, trails obediently after as they head back out to the parking lot. He knows what's coming here – it's not like there's anything to pack, after all, not like they'd just decided to stay at the Roadhouse for a day or two. This is a case of not fighting in front of Sam, because that will turn to fighting with Sam because the idiot has taken it upon himself to defend his brother or else just to fight with Dad whenever possible – feels more like the latter these days. Jo gets a smile that's supposed to read as families, huh? Crazy as they pass her in the hallway.