There may be two reasons why he did this. First, he may give up on himself. If so, let him give up his present idea. After all, it is very important to learn knowledge now. If you muddle along there, you will be ruined sooner or later, and you will accomplish nothing in the end. Second, he may really want to "lighten the burden on his parents" as you said. If so, you can boldly let him try, let him drill more cigarettes in his nostrils, let him know the hardships of making money, let him turn failure into strength in the future, cherish the present and work hard for the future!