i dont know much about the legal rights of all parents involved, but in my opinion, the best thing for the child would be for everyone to sit down and talk about this. if youre afraid the child is a danger to herself and others its important to communicate this with the people she currently resides with. i'm sure you all want to do what is in this childs best interest and the best way to go about that is to sit down and discuss. is there a case worker involved that could possibly mediate on your behalf?
wishing you best of luck and keep us posted on how it goes.