In fact, the issue is much more acute than it seems at first glance. The student's mother is worried about what gambling can lead to for her son, because he has no regular income, and she is well aware that gambling requires money.
I would advise this guy to quit gambling and save his mother's psychological health, or to find a part-time job and spend the money he earns as he sees fit. In this case, the guy will have a job and his mother will not worry.
It is good when relatives know what you are into and watch for changes in your behavior.
I believe quitting gambling would be an easier thing for him since he is too young at the moment and managing his studies and a job will be very difficult for him as he isn't mature enough to be able to do that and he has a lot to learn for now. So his mother must make him sit with her, let him know how much she cares for him, and that what he is doing isn't good for him in the long run and she doesn't want him to go on that path as that can affect his future.
I'm pretty sure that the guy will understand if his mother does it with love because there is nothing more powerful than the love of a mother in the whole world. So, I believe it's his mother who can actually help him get out of gambling and get into his usual routine and life with his family.