Cas is trying. It's not good- hell, it's not perfect, but it's a start and Dean is trying really, really hard to be grateful for it, because they're friends. And he's had a helluva time lately, and he wants to try and fix this, wants things to be a little less shitty and a little better, so shoving it all down and thinking about it later is going to be the only option.

"Yeah. I'm-- yeah." Not that he doesn't believe you, of course, it's just because he really, really wants to check on his little brother. He has to.