Occasionally, Dean will get the sense that Sam's not right.
It's been mostly smooth sailing since they'd thwarted the apocalypse, but sometimes Dean worries that Lucifer did something to Sam's head before his brother had driven him out.
Not that Sam's disabled or anything - no, Dean wouldn't ever consider that possibility, because, come on, it's Sam - but sometimes he'll stare off in space a bit too long, sitting up just a bit too straight, and Dean will feel like he's stepped into uncanny valley. Like maybe Sam's not - well, he is, okay, he's human - but maybe he forgot how to be, just a little bit.
It's disconcerting, to say the least, but then Sam comes right back when he notices Dean's frown, and he apologizes, and Dean never knows what to think.
It's all good then, until Sam orders a burger with extra bacon, or lets Dean have his way much too easily, but Dean tries not to let it bother him so much. Live life to the fullest; don't sweat the small stuff, right? It's like a near death experience, he surmises the best he can. Having the devil inside your head changes people, if even only for a few short minutes.
Sam doesn't talk about it though, and Dean wishes he would. Maybe it would make things a bit better when Sam's looking at him like he's never truly seen Dean before, or saying something stupid and dangerous like 'I love you'.
No, Sam's never told Dean how he managed to beat the devil, past "It was you,", never elaborated on the horrors that must have been forced on him, or what it was like to not be in control of his own body.
Honestly -
and he doesn't even want to admit it, worried that looking too close might mess everything up all over again -
Dean's afraid to ask.
