If she is being sexually or physically abused, then she should talk to a trusted adult such as a teacher, counselor, or pastor immediately. She can call the police or child protective services if necessary.
Be very careful of stepping into the middle of this. Of course if someone is being abused you should say something, but make sure you really understand what is going on. It would be best if she would make any reports herself.
A minor can't just move out and be on their own, the state will want to be sure she lives somewhere safe if she cannot live at home.
My comments are general statements of the law in Washington and are not meant to be legal advice.
Specific legal advice requires an in-depth interview, review of past or ongoing court or agency actions or cases, and an evaluation of the special circumstances of each case.