My 16 year old niece does not want to return home?

I have a 16 year old niece who does not want to return home after summer break is over. She wants to stay living with me and I would like for her to stay. Does she have any say in what happens? Her mother told her she is coming back home. Her dad has been abusive to her in the past and both parents are alcoholics. Her father has been accused of messing around with little girls age 11-15 but never convicted. What can we do to allow her to stay with me or is there anything I can do to help her not go back in that home?