Boundaries in Grey skies

I have a half-sister who is 20 and has two kids. I found out about her last year. My immediate family doesn’t think I should be in contact. But I care about her well-being and the well-being of those children, especially the children who deserve as much opportunity as anyone to grow up in a functional situation. At one point she left the kids with relatives and took off. But she is with the kids now and she left their abusive dad. She says some stupid inappropriate things on Facebook, which I think could backfire if she wants to try to get somewhere further in life. I don’t know if I am strong enough to help her. I think she is very closed off, her walls are up and I don’t think she is used to talking about her feelings. I just wish there was some better support around her. She lives in a very remote, small community.