Your post made me sad. Sorry, but I think you are way too punitive in your approach and need to learn more about ADHD and anxiety. Your daughter has done a great job, it would seem, in many ways.
It was YOUR job to advocate for her, urge her to register with the Office for Disabilities, and obtain accommodations, including, perhaps, a reduced courseload. Taking three classes instead of four can make a huge difference in someone’s life. (There are ways to proceed with reduced courses and finish in an affordable way.)
Even your attitude to the dance class reeks of condescension. Dance is a legitimate pursuit. Try reading Howard Gardner’s theories on multiple intelligences. And dance is great for those with ADHD.
I suggest you get a therapist, yourself, and come to a more collaborative approach with your daughter. Stop putting it all on her. Work with her.
Work can be really helpful for kids with challenges in school. Help her find other areas where she can succeed. More dance? Volunteering? How can this leave of asence be more than meeting a curfew, doing the dishes, and working part-time locally? Do you have a friend in NYC she could stay with? Is there an internship that could inspire her? Look into National Outdoor Leadership, wilderness programs that have helped many young people. Whatever interests her. Be creative as long as it is affordable.
Going forward, does she want to return to the same school?
Landmark has programs for kids in other colleges. The coach was a great idea, but did it come from her or was it imposed? It may be that she will decide not to return. In that case, there are many ways to finish school or make progress: CLEP’s. community college, various online and continuing ed programs. One of mine is doing the adult learner program at Lesley U. in Cambridge. Mixed ages, all kinds of back stories. She takes two classes per semester, one at a time. She has severe ADHD and the road has been long but she has never given up her dreams.
When kids come home, they often continue the sleep cycle they had at college. I remember working 3-11 and staying out until 3 or so. Make sure she is safe, but it works best if you treat her as an adult, as others have said.
Paradoxically, the more you give her autonomy, the more input you may have. ADHD and anxiety are not the sufferers fault. There is a good book entitled “The Myth of Laziness.”
I know how hard this is, and I am sorry if I come off as unsympathetic. We have all had the feelings you are having. My post may seem critical but I am trying to help after many years of this, so hope you are not too offended to accept it.