Thanks guys, much appreciated. =)
Yes it's like I said originally, action other than passive would make things worse. She has told me that he denies ever doing this stuff when she tries to bring it up, as does her mother. Her parents want her to have a car before she moves out, and if she doesn't obey them, she'd leave home 'on a bad foot' so to speak, which she doesn't want. They believe that as long as she's under their roof, it's their rules with zero negotiation.
I've been hesitating over moving up to Perth to study lately, but after her telling me she'd move in with me, I feel like doing it just to get her out of that house. I'm horribly worried about her...
Thanks again for the advice, guys.