Does anyone have a friend like this?

Basically mental illness runs in her family and i think she might have a problem.. The way she goes on sometimes. She never think she does wrongs. She might not answer the fone or get back to you for weeks and thinks its perfectly normal. You make plans with her and she either cancels or ignores your phonecalls. Shes goign out with a guy who i think is possibly gay and shes mad into him. She started in college and made a few new friends... they arent real friends its just people to party with and its already the start of the summer and they have no contact. Like what to do with a person like this?? She was always ignorent and quite rude at times but her ignorance and lack of communication just gets worse. She does it to all her friends like.... grrrr