I love this moment so freaking much. Not because of Dean - though I do always enjoy a little concerned manhandling - but because of Sam. He’s in pain, he’s scared, he’s confused, he’s seeing this awful death vision. And in the midst of all this turmoil, his first instinct is to reach out and touch his brother, grab onto his shirt. The Winchester boys do this sort of thing a lot: the “This is real, you are real” confirmation touch. When they come back from the dead, they hug each other. When Sam is trying to tell Dean he’s real in What Is and What Should Never Be, he shakes Dean’s shoulders. When Dean is trying to tell Sam he’s real in Hello Cruel World, he takes Sam’s hand.
I think this is why they walk as close together as possible, why there’s a total lack of personal space. I think it goes beyond just being brothers - it’s this constant reminder that yes, he’s still here. I’m still here, no matter what is happening inside my head.
This, above all other things, is real.