Just made plans to go to a friend's neighborhood for trick or treat just in case.

I'm pretty sure this is deliberate. When they were together she used to do the same thing. She would make the entire plan and THEN ask him or tell him about it. I'm talking "hey, I'm going to Florida next week, I've already bought the plane ticket and gotten the hotel, oh and by the way the kids are staying with you" so that when he says no, he's the bad guy. He fell into that trap for a long time knowing that his options were to agree or to fight, and he was tired of fighting.

He did stand up to her and tell her no again and was very firm and clear this time. She fought with him. She told him he was a bad father and this was not coparenting. It's been a fun morning.