I think he needs to discover that insurance selling is no easy money for himself. He is also suffering from composition fallacy.
From Wikipedia's article about it: "If someone stands up from their seat at a cricket match, they can see better. Therefore, if everyone stands up, they can all see better."
But in reality nobody will see better if everyone stands up. If everybody starts selling insurance, there will be insane competition for potential clients and your son won't make money.