This does sound difficult for you, Skydancer. I sympathise. In my city there is a counselling centre where counsellors volunteer and you can give a donation according to income. I think trainee and new counsellors get experience there. If there is something like that near you, that might help. Ours is called the [Name of city] Counselling Centre.
Like Nannee49, I have heard that there seems to be a link between inflammation in the body and depression. I believe a good diet can help with that (fresh, unprocessed food and lots of vegetables and fruit).
Professor Tim Spector and others think, based on research, that diet affects the microorganisms that live in our digestive systems, which affect inflammation in the body, which affects whether we are depressed (among other things). He recommends, besides fresh, unprocessed food, eating as many different types of fruit and veg each week as possible (preferably 30 types a week), along with olive oil and foods that contain polyphenols, such as good-quality dark chocolate and berries. Also fermented foods such as kefir and kombucha. He says these foods nourish beneficial microorganisms in our bodies. But ultra-processed foods nourish harmful microorganisms.
If your daughter was willing to adapt her diet, that might help. Tim Spector’s books, like Spoon Fed, are available inexpensively on Kindle, and videos featuring him are on YouTube. If you liked his ideas, maybe you could send her a link or buy her a book.
Has she tried exercise? Jogging used to really help me when I was depressed.
Something that has really helped my self-worth (since becoming a Christian) is my Christian world view and relationship with God. I know other people have found the same. I would recommend your daughter to look into Christianity for herself, if she hasn’t already. Alpha courses are generally good and people usually enjoy them. They usually involve a meal, then a short talk, then discussions in small groups. When I have gone to or helped on these courses there has been a friendly, supportive atmosphere in the small groups which your daughter might like. There is no pressure involved.