Depression

My friends recently told me she has depression, but I know for a fact that telling her parents will only make things harder, as her mom is very sick and extremly worrisome. I have never talked to her about it face to face, only on the phone and I really don't know what I can do to help her??? I've suggested seeing a doctor but idk if she has tried. Also I know she is self harming but I don't know to what extent. I'm super worried but I don't know how to handle this. Any advice would be appreciated!