Damn... Fedup has spent as much or more time dealing with the family law industry as I have!
Great info - good of you to take the time.
Document, document, document.
...and frankly I love the idea of letting the cops know he is driving a multi-ton unguided missile (van). Honestly I think I would try to find out where he is on Friday night and driving drunk then call the police anonymously. That might bother your conscience but it isn't just best for you and little guy, it is being responsible by keeping him safe and protecting those on or near the road.