What can stop a chronic gambler from gambling? Funny enough, I'm still looking. There's nothing as elating as knowing your chips are piling, but it can be so depressing when it all comes crashing down. As the op mentioned, there are health issues and money issues involved too but a gambler won't mind going as far as stealing when he has exhausted all the avenues for borrowing because he believes the next game will be winning number.
There are people who have self control, but not all.
I think even if a person borrows money to gamble, this is already a gambling addict who urgently needs help from specialists. He is unlikely to cope with his problem himself. The person who is ready to steal for the sake of another gambling game obviously has problems with his head. Such a person should be in prison because he is a danger to society.