This will definitely be a problem for him, not only in gambling but in real life. When he has to face dark times with little earnings and a lot of expenses, how will he do if he doesn't know how to manage money properly? He will get into debt and this will lead him to a self-destructive spiral.
That's what often happens to gamblers with small incomes. They take too big a risk to gamble. Of course, they don't have bankroll management and just enjoy the game to get lucky. If not controlled, then everything can be lost.
All is different from rich gamblers who do have good financial management. They know the limits of the risks they can take. Although it is possible that those who have a lot of money will also bet impulsively.