Is my friend in a bad relationship

Okay my boyfriends younger sister has been in a relationship for a year now but everynight they fight over stupid things and when I say every night its every night I admit she has starteed them but I think she needs to lay off him because she blames him on running around on her the only thing they both go to different schools shes a sophmore and hes a junior at my school and she goes to a school like 3-4 miles from my school I think they need to work things out or just be friends I stay out of her relationship but she calls me and tells me there fighting again and what there fighting over and I ignore it now I dont answer the cell phone when she calls I dont want to hear it but what should I do the next time she wants to talk to me about her unhealthy relkationship by the way my relationship isnt this horrible I may arugue with my boyfriend but we talk about it they dont they just hang up on eachother

well I think they should trust each other more than they do an I don't think you should ignore your friend be a true friends an listen to what she has to say or tell her the truth that you don't want to hear anymore about it because you don't like to be in there business

I don't believe you should interfere in this relationship but life and relationships are all about learning about yourself and the opposite sex, as well as the dating world...You can observe and maybe throw in an opinion every now and then but don't try to persuade her of anything unless she asks your opinion, even then I would tread lightly because I know woman like their little tests and mind games that they play with each other...Just take everything that happens in their relationship in stride and learn from their mistakes.

well shes my childhood friend and the only friend I had I want to tell her whats on my mind but dont want to hurt her fellings

update he broke up with her well not in the nicest way he told her to f#ck herself and it was over they been together for over a year

well they are taking a break right now 3 nights ago he we going to the rollor drum and they were fighting ( on the phone) and he was going to get one of this girl that was a friend to go and beat her up so me and my boyfriend went with her and she didnt leave our sight and by the way she was my boyfriends younger sister but no one ever showed up so that was good