I appreciate this post. Not the easiest read, but certainly helpful and good advice. I'm trying to figure out how to deal with my brother going forward. Right now my solution is that we're not going to concerts together for a bit. Unfortunately when I tried to address the issue with him today he is being even worse and I think trying to antagonize me, so I've been ignoring him. Of course, there is also the "if he is an asshole when he is with you in the future, even when not at concerts, call him out on it" approach that you have recommended and I agree with that as well. (Side note: as for the bartender...yeah, I know haha. I like to flirt with bartenders. I think expecting any more out of it is a bit of rookie mistake.)
I always flirt with bartenders. If you do it right, they're generous. If you do it wrong, they let you know. I love the game, even if I don't get to play for keeps any more. The grand take on all this is that you aren't entirely comfortable with your brother's behavior. That may never change. You owe it to yourself, however, to make sure you don't get any on you in the future. That's part of maturing to adulthood - making dispassionate decisions about family. Good luck. My own family is a mess. It's far easier for me to give this advice than follow it.