Sam never says anything about it, but whenever Dean borrows his clothes, he knows something is wrong. It doesn't happen often, just now and then.

Like when Dean is sick.

Then he usually picks one particular hoodie, the charcoal one. It's Sam's favourite and he wears it all the time, but he willingly hands it over to Dean, knowing that it will comfort him. Most times, when Dean takes it from him, he will be snarled at for being a girl. That's when he knows that everything is going to be okay. Only when things are really, really bad, like the time his heart almost gave out, Dean takes it without saying anything.

His older brother always seems to shrink when he wears Sam's hoodie which is a few numbers too large for him. It makes him look small and vulnerable, almost like the child he never was.

As soon as he's well again, the hoodie is back in Sam's bag, as if it was never gone, and they don't say a word about it.

Or when Dean is scared.

True, that practically never happens. Because Dean Winchester doesn't get scared. But when he comes back from Hell, Sam hands him some of Dean's own clothes that he had kept in the trunk of the Impala, because he has never truly accepted the fact that his big brother is gone. Only when Dean comes back from his shower, he wears Sam's clothes instead. They have lain in the bathroom where Sam had undressed the night before, so they aren't clean and probably smell like Sam. Maybe that's exactly what Dean needs. Because he remembers Hell, because he is scared that his return might have been a dream, that he is still down there. He needs Sam to make sure he's not.

And sometimes Dean's just tired.

Not tired from a hard day's work (which they always have), but tired of it all, of travelling, of fighting, of life. Sam can tell from the look in his eyes, from the lack of snarky comments. Then he'll find a pretence to leave Dean alone for a while, just for a few minutes, never for too long, and when he comes back, Dean will have picked a shirt from Sam's bag and he'll wear it as if he's never worn anything else before. He'll fall asleep then, still dressed, a piece of Sam wrapped around him to guard him from bad dreams. The next day, he'll feel better.

Sam never says anything about it. He's just glad he can give Dean, who always has a hard time accepting affection, this anchor, something to hold on to. He knows that someday, it won't be enough. But for now, it is.