Cut her off. Her entire future outlook on life may depend on your doing the right thing, the hard thing, whether you can claim her as a dependent or not. She clearly demonstrates that she has no desire to depend on you for anything other than money. This day had to come, it just came sooner than you expected. So, grant her the deepest wish of her heart: to be unaccountable to you. Will it cost you? Yeah. Is it fair? Hell no. But why let her own you and your peace of mind?
Your advice is very sound, but let me clarify one thing. I would never really consider removing her from my insurance. My point was that I'm changing the plan so that
if she needs medical attention, she won't be able to get it in her college town. She would have to get it in my town. I guess it was kind of a carrot and stick approach to get her to kick 'Gary the retard' from her apartment. And yes my premiums will be lower without her option to seek treatment anywhere. But as far as the cash is concerned, below you'll see what I would consider a perfect resolutiuon to this mess.
1. I drive over to Ames Iowa and grab Gary the retard by the throat (with a good Zell Miller type grip.) I tell him times up junior and drag him and his stuff to the street. When he gives me the mean "I play college baseball look" I return with an angry 6'2" 258# 38 year old shaved head half Irish half Italian fatherly stare. He then proceeds to the parking lot thinking about which freind he can call to shack-up with that night.
2. I resume paying the tuition. And change the healthcare back.
3. My daughter has a nice young ladie friend move in to help save on expences.
4. My daughter understands what I did and I am considered a hero.