WeHi, I understand why you would be concerned about him since gambling could be a dangerous way to support himself. It is much better used as a hobby rather than a way of life. He may have an addiction. In this case I would suggest he gets help for this. He may be unable to see things from your view if he is addicted. I would express your concerns to him trying not to judge or point fingers. Be very sincere and show your love and concern. This will help him to not become defensive. Sometimes tough love is the best way to go. Right now he is living with you , so the power is in your hands. It is your roof and your rules. Despite his age he is sti being dependent on you. You may want to consider letting him know that he needs to get help and do something productive in order to stay with you. If he is grown enough to make his own decisions then needs to also support himself in order to make his own decisions. I know it is difficult as a parent, but sometimes actions is what will help change a child to grow into a mature individual. It can be a tough road, but then in the future you will see results from your firmer actions. I wish you all
well and please let me know if I can be of further help.