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.