Look at the way Sam slumps against Dean, like for a few seconds he doesn’t even have the physical strength to keep himself upright anymore and he just falls against Dean’s chest, his chin coming to rest on Dean’s strong shoulder while strong arms wrap around him, securing him, comforting him, just plain holding him for the sake of holding him. And slowly Sam finds the strength to return the hug and his arms cover his brother’s back. Sam’s exhausted beyond any exhaustion he’s felt before but he uses the last ounces of strength he has to hold onto Dean for dear life.