As sad as it is bound to be, I have a sinking suspician that this issue will resolve itself fairly quickly.
Either Dad will see what Amy is doing and it will destroy their marriage, or he will eventually follow suit, which will lead to the erosion of the father-daughter relationship. Your daughter is already trying to avoid her visitations with him, and she is only 13. Just wait a year or 2. Unless he gets his head out of his ass, just TRY to make her see him at 15…
These are all unfavorable outcomes, but this woman is toxic, and the reality is that nothing changing would be worse. Feeling unwanted by a parent is incredibly damaging for anyone, and the sooner your daughter independently puts her foot down, the less extensive the damage will be.
I am so sorry you both find yourselves forced into this situation. I wish you luck.