A very common motivator is being a good role model for your children.
Showing your kids what is right is one of your main jobs as a parent. He's got a roof over their heads. He's got them fed. Now he needs to show them what is important.
250k to a multi-millionaire isn't much if he manages his money well.
It's may be a lot to you or me, but to him it might be a small price to teach his kids a very important lesson that they will be able to pass on to their kids.