I'm going to shout at my little brother asking why he was only wearing his underwear while he was talking to his crush on xbox
That's a little inappropriate. Why did he only have to wear that?
Apparently his crush told him that he should be wearing nothing when talking to them.
Well they probably shouldn't be doing that when other people are in the room, then. That's not the best idea.
I can't believe this. I'm going to humiliate him and make sure everyone knows that he's the embarrassing kind of brother.
That may have been embarrassing to you, but I believe there is no reason to embarrass him back. This is a private affair, and you can just tell him to do this when no one is around and to keep his clothes on when you are there. When he's alone he might able to bond better with her too.