Just don't let her get her own way, if she wants to sulk and scream, let her...walk out of the house and go for a walk. Let her dad deal with it. She'll only blame you for interfering. Then just sit her down and explain that you don't think of her any differently to your own kids, you love her, but you're not gonna let her get away with murder. Maybe ask her if she has a problem and try and resolve it, but just lay down your rules. She may be his daughter, but it's you she's disrespecting.