You get to do nothing. Mom can play whatever game she wants. Dad didn't forfeit anything unless the papers state he forfeited visitation. Apparently they don't. So he can pick up his child. Maybe he doesn't recall that this weekend is his holiday. And maybe MOM could cooperate with the man she chose as a father to her child.
Parents should remember 3 things: Love your kids more than you hate your ex; when you have children the relationship with the other parent is until death; your children determine what type of nursing home you end up in.
Nothing stated by me should be taken as giving you legal advice or forming an attorney/client relationship.
Attorney-GAL in Ohio.
I've removed the knife from my back, polished it, and will one day return it -- long after you think I have forgotten.