How do I support? Tw: mentions of self-harm

Recently my nibbling came out to me as non-binary but is unable to come out at home to the rest of the family. They really just want to be themselves but our family might not be supportive of how they identify. How can I support them? They are underage and I live in a different city. I just feel so frustrated because it feels like there's nothing I can do. When they came out to me we cried because they didn't know how I would react and I love them so much, I've seen them grow up and I just want them to be happy .

Also how do I help them heal? Physically and emotionally...because they also told me they've been struggling with self harm...

I just want to know what else I can do besides listening to them and accepting them. That's done and covered 👌🏽 but I want to do more