Should I forgive my "friend"?

Ok this girl seems like a b**** and a priss but you never know what's really going on inside someone's head. She could be hurting from something inside and is just taking it out on people. You should talk to her and find out why she is acting like that. If she starts getting offended them stop talking to her cause she doesn't seem like a true friend. Just ignore her when he starts whining because she is doing that for attention. Let your brother deal with cause he obviously chooses to do that. You shouldn't waste your time on her. Focus on other things and not her cause that sounds like someone that just starts problems. I would just leave her alone and let your brother deal with it and just stay away from their problems. Don't cause yourself more stress by dealing with something you don't have to. Ignoring other people when they bother you does wonders :)