Try not to feel bad OP. Your brother and your friends shitty girlfriend should feel bad. Just be a good friend to your mate and be there for him in the coming days/weeks when he needs someone to lean on. Do make sure you tell him though, it's the right thing to do. Best of luck x

Sounds like your best friend was justified in having doubts about his girlfriend cheating. It shouldn't effect your relationship with him - just continue to be a good friend to him while he deals with it.

this is between the three of them and no matter who did what wrong they deserve a chance to work it out without op interfering; op, tell your brother and the girl to fess up or you will spill it to your friend. also ydi for speaking on someone elses behalf without permission. not your place. and again it does not matter what anyone did.

kill that bitch

You know what they say, a picture's worth a thousand words.