I feel very bad for her. Obviously, the girl is playing the parents.
There is nothing you can do in these situations other than to let the professionals handle it. It’s beyond tough love.
I’ve had children like this turn on their parents, and murder them in their sleep.
Get her thru these tumultuous years and when she turns 22, she’ll be normal and hopefully repentant.
I’m sure the ass hat father, takes the girl’s side.
She may be less nuts but I wouldn’t count on “normal”.