Hello there. So, you say that this person isn't your friend anymore? I am pointing this out, because depending on why that is, the solution could be different. Either way, I'm assuming you care for her if you're asking for help, so I'm going to call her your friend here. If you guys drifted apart because of her living conditions, try speaking with a guidance counsellor first. You don't have to name any names, or go into great detail. You can generally describe what is happening, and see what options they can give you. For example, has your friend spoken to anyone about her situation? About her wanting to harm herself? Be sure to let her know you're there for her if she needs to talk.
If you don't really know her and aren't so close to her/never were close to her, maybe you don't know the full situation. In that case, it could be more harmful to butt in then it would be to leave her alone.
All in all, no matter the situation with your relationship, maybe post some details (again, no names/details necessary) here on the site, or speak to a trusted adult about it. You may not have thought about all of the possible solutions. You seem like a good person to want to help. Remember sometimes the solution isn't easy or painless. If you want to talk more about it, send me a message anytime. All the best!
