If your friend refuses your help, there is not lots you can do. You could confront her again with the problem, and keep asking, but this might make your friend drift farther apart from you, and she needs friends now more than any other time in her life.

You could call Child Services, and they would look into the problem about your friends parents abusing, hitting, her. But it's up to you if you think this would be a good idea. Sometime it helps, but other times...

It's a difficult choice, but it's either that or ignoring the problem, and that could really cause some trouble. Physically, and emotionally. Hope this helps....