Why do people ignore her?

When we went to school last year, I had this friend who used to hang out with this group of kids. She would eat with them, talk with them etc. but whatever she did for them, they wouldn't ever look at her; talk to her. She cried almost everyday, because besides me and my two other friends(Steph and Liz) they were the only people she really wanted to be with. Even if they ignored her, she still stayed, just waiting to cry about it later. Now it hurts me and probably other to see someone that they care about cry. She was going through a lot back then and still is; she hurting and nobody except me will cares. Me and my other friend Dar are the only one she will tell her problems to, and we can't do anything about it. She said to me( well emailed me) a couple weeks ago says that she was going emo just because of them, and now that Dar is getting annoyed with her, now I'm the only one she can turn to. Those so-called friends of hers could care less about; she feels that they hate her and want her to die,but she still wont leave. She knows I'll always be there for her and comfort her, but I fear that those retards are going to hurt her so much that she won't be able to take, even if I help.