Did he drive the kids to school before he showed up stinking like alcohol? if so be sure this is documented.
I know you are not thinking along this line, but child support and a job are HIS responsibility, just like keeping up with support payments. In MY state, deadbeat parents that don't pay, do not get income tax refunds, lottery winnings and lose their driving privileges,also an automatic arrest warrant.
so if he wants to keep his privileges, he will borrow from family to make the payments up to date.
This was recently on the local news as the state of NJ offered a week of Amnesty to deadbeat Dads who came in and set up a payment plan...one guy owed as little as 6K in arrears and was thrilled to get his license back....
maybe you can Cobra the most vital of health insurance....reducing the co-pay?
I hope you can find a good well paying job that will give you peace of mind and less worry.