Your daughter is 21.
She is an adult.
You can not force her to do a thing, or get help for her.
She is on medication.
This is actually between her and her doctor.
So the real question is what can you do for you. Right?
Because if you don't cope, you won't respond correct to her.
This is a difficult transition, and the best professional for you to see would
be a PhD clinical psychologist trained in family therapy.
Not that your daughter would go with you, but that this will help you, and your daughter could be invited into sessions when you are ready. This in fact might help both of you at that point.
Her condition sounds bi polar to me, which can have hallucinations.
That is the best educated guess.
OK, so you might have more questions or want to give me more information: Please use reply to expert if you have further questions. When you are ready, please click a positive rating [hopefully excellent—that’s how we are paid, per rating]. If you forgot something, come back. I am here http://www.justanswer.com/medical/expert-dr-thomas/