His daughter was given POA while in coma. My fiance lives in a nursing home now but is alert and awake. His daughter says I'm not welcome to visit him there because they don't like me, but we loved together and were together. It's obvious he wants me there but the nursing home makes me leave when I go there. This is so wrong but do they have power to do this?
Does he know that you are being kept away?
He needs to know or he will be believing that you abandoned him in his hour of need. I would get word to him and ask him to tell the nursing home that he wants you there. The POA is only whilst he cannot make his wishes known and is not of a sound mind. Sounds like he no longer needs anyone talking on his behalf if he is awake and alert.
That would be my 1st step.
So I don't know what the situation is but I do know it's not that.
How long is it since your fiancé recovered from his coma?
Seems to me principle doesn’t want contact, but who knows.
Isolating a person just because a POA says so may be not acting in his best interest. For instance, if you were abusive and the daughter knew it, the daughter's actions make sense. If the daughter is refusing you just because she can, "they don't like me" [who is "they" and how does that matter?], then I'd notify Social Services or Department of Aging and file a complaint. Have them find out why the daughter's isolating her father and how that's in his best interest.