[He can't handle the tears. They are some kind of magic that he has no resistance to fight against. So she brings a hand to his chest when she shouldn't and he pulls her into a hug when he shouldn't.
Dean's gone. Cas is gone. Bobby's not around. His dad...
There's no one left to tell him when he's off the rails. To tell him what he should or shouldn't do, so right now he's going to hug the girl he cares about because there are tears in her eyes even if it feels right and wrong at the same time. She's not the only one who could use the hug.]
You too. You didn't do anything wrong. [She wanted to survive. It's the most primal drive anyone can have.]