Ban the gambler? No. I am just the manager, the owner will fire me if I do that. Business is business and if he won't stop then it won't be the casino's problem as long as he is not making any scene. (loans with other gamblers, becoming a beggar)
I am more curious about the guy. If he comes back there everyday then it must mean he is rich but why he is being stopped by his nephew.
Maybe it's not about the money, it's the "time".
Indeed, as a person we can say that he is only concern to OP, but then as a casino manager he should be fired. A player's information should not be expose to public or it should be keep confidential, but then the manager keeps talking about his family that is not directly related to the game I think there's no information sheet that will ask you that thing so I think the manager get the news outside.