Gosh OP, your DD sounds a lot like me a few years back. I applied to do law at 17, was accepted, but just broke down sobbing one day and decided I wanted to go to art school and have a career in art, as I thought that was where my heart lay. I got into art school, but it didn't magically fix my life as I'd expected. Through my 4 year degree, I started to have panic attacks and depressive episodes which got worse as time went on, as I was so aware what a precarious career path I'd taken, and was terrified about my future. I was finding out, more and more, that I couldn't handle it . When I got my degree, I applied to do a Masters at uni in languages and was then offered a salary to do a PhD. OK, academia's not the most stable career field, but I don't feel the same sense of total loss that I did at art school.
I know a couple of people from my year who are now making their living in their creative field (graphic design) but everyone else I studied with does a regular job as well as their creative practice.
Your poor DD sounds so lost and, from my experience, the precariousness and scope for rejection in the creative sector might not be what she needs right now. One thing I found always helped my moods when I was art school was volunteering and teaching in projects where I could put my creative skills to good use in the community. Would your DD be interested in trying something like that? If I'd stayed in art (tbh, I had neither the passion nor the talent), teaching would have been my chosen career, because it stopped me ruminating about my own worries by making me focus on something else.
I think the whole idea of making what you love doing into a career can be scary, because it becomes involved with rejection and finances, and that can spoil it for you. These days I see myself as working to live, not living to work, and life's better for it. I still love my craft, still do it when I can, but feel better that it's not getting graded.
She sounds a sensitive soul, and I think that looking at art as a means to help others by teaching (or even art therapy) might be worth looking at. Good luck, OP, I wish her all the best.