Dean doesn't know how long he's been sitting against the pillar on the bunker floor. Must have been a while, though, because he seems to have cried himself out. And Kevin's eyes have stopped smoking. Oh god.
Everything happened so fast - the spell going wrong, the angel taking over Sam, Kevin dying. There is no Sam? Dean almost can't wrap his head around that one.
He knows he should be doing something. Calling Cas. Giving Kevin Freakin' Solo the hunter's funeral he deserves. Maybe even pummeling Crowley til he coughs up some useful info for getting that damn angel out of Sam.
But he can't.
The feeling that his soul is being shredded and ripped from his body has been temporarily replaced by numbness, and right now that's better. He's afraid that if he so much as moves, he'll lose that, and if he loses that, he may just lose himself for good.
Because everyone's gone, and he's alone, and oh god he can't do this again. Even though he knows he's gonna have to pull himself back into the world, take care of Kevin, and figure out what to do next, he's not ready to face reality yet. He's not ready to face the horrible new world that's waiting for him.
So he sits on the bunker floor and wraps himself tight in that warm cocoon of numbness. Because for now, the world can fucking wait.