he can refuse to pay all he wants but all you have to do is file contempt of court and they will make him pay. the 3rd time i had to do that, the judge wouldn't even let him leave until he paid the $1200 he was behind. he was handcuffed and shackled and held in a room where he was allowed to make a phone call to his wife to bring the money. the judge told him he wasn't leaving the building this time until i had my money. needless to say, he can't refuse to pay....
also, on the first issue, i don't know about the laws in your state but in my state, this re-opening would just piss a judge off and he would get nowhere.
You don't have anything to worry about.