I will advice him to stop gambling. I will not help him at all than to buy only food for him and it will not be expensive ones but cheap ones. He should stop the addiction and start a better life. It is as simple as that.
That's the best thing to do. Avoid giving him cash but assist him with foodstuffs so that he wouldn't have any excuse to say that you didn't help him when he was in need. One thing that I have come to understand about addiction is that if the addict is not ready to come out from addiction, there's nothing anyone can do to help them.
An addicted gambler will always be broke because whatever money that he has will be used to gamble because they cannot control themselves anymore.