Well, if she's being abused in any way, she needs to get out of that situation sooner rather than later. I suggest you urge her to tell someone about it. Be there for her and encourage her to be strong enough to say something, so she can get out of this situation. Maybe there's other family members she can turn to, or she can tell your parents and they can help contact social services, so they can get involved and help your friend. If she can't do it or she's afraid to, I think you should step in and tell an adult. Even if it may upset her, it's going to be better for her in the long run. Just continue to be there for her and encouraging her to do what's best for herself.

I hope this helped.

Tell her to tell someone and that you will be with her through it all. She needs to know that everything will be alright. You need to get through it.

^ Like they said, tell someone. I know it sounds like one of those stupid educational videos about stranger danger, but telling someone is the only good solution. If she won't then tell someone you trust. (Parents, teachers, principal, police, etc.)

as everyone has already said, you need to help her to get out of this situation, try your best to get her to tell someone old enough who can help by calling social services. if she find that she cannot bring herself to telling someone then you should tell your parents/teacher etc basically a person you can trust, and then they can help you to get her out of this, she may be upset if you do this, but down the road she will thank you sooo much for stepping in and helping her.

What do you mean by her being abused

This is serious. What kind of abuse are you talking about here? Is Sasha being physically abused, verbally abused, sexually abused, or emotionally abused?