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.
If you are very sure the money will be used for gambling, there is no need to lend it to him because if you choose to give him the money and he ends up using it for gambling, it means you are encouraging him to continue with the uncontrollable gambling. This is even the best time to give such a person advice; it will help more than lending money for gambling. For people like this, it is important to know what they really want to use the money for because it can be something important that they really need help with, but if it is for gambling, there is no need for that because it is not reasonable to take a loan for gambling.