I want to add one thing. Sometimes I do think that my son is on a spiritual quest. He is trying to understand his reality and his life in terms that are quasi-spiritual or cosmological. A lot of it is nuts, I think, but as Crayola points out, there are aspects of your daughter's beliefs that are reality-based. It gives me solace (some at least) to think that my son is trying to work things out for himself. It is not only a manifestation of mental illness. It is a trying to come to grips. I see over time that some of his views are moderating and more reality based. As I study spirituality and meditate more and more we are coming together (a little bit) on how we approach the world.
That said, I want to tell you that I think you are doing masterfully in an impossible situation. I hope you keep posting here. You have a lot to contribute on other threads too. It helps.