These beleaguered new parents rationalize that their situation is different from yours or mine. So again, only after we've lived through some of the pain, can we be open to finding ways to alleviate it. Be sure you get the message of love across to all your children. Don't become totally focused on just one. Build a united front among family and extended family in any dealings with the victim.
Agreement is crucial.
Set definite limits to your level of tolerance for this behavior and follow through on enforcing them. See that your daughter has the most competent professional help. Step back and allow the experts to deal with her. You stay out of it as much as possible, unless asked to assist. TRY to relax.