IRMAT, He just might fool you and come up with the money for the child support. You just never know w/them. That's a lot of money to blow in just a few months. He's not hitting bottom yet and it's going to be a while.
Do what you have to do to make the holidays special for you and your family. His memory may not be that good, but trust me, he can and will remember certain things that are important to him at this time. He needs to face the consequences of his actions and he just might meet up with old scrooge before the year is out.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.