If you figure out the REAL source of his income you likely have everything solved. He may have had his family and others thinking his millions were handed to him by the casinos but it is simply IMPOSSIBLE. The high stakes video poker machines he was playing are 97% payout machines, meaning if you play every hand to perfection you will LOSE 3% of your money long term. He was obviously using the VP machines to launder his money and hide the true source of his income.
We have a few of those millionaires in my Town.