It was pretty obvious that Anthony didn't want to have anything to do with his father's business (or his father, at that point), so I'm assuming he wasn't counting on the family's fabulous wealth to cover him if an opera career failed. Michael's advice to him was as if he were intending a career that would sustain him and his family, unsubsidized. He was saying, "get the law degree and then take up opera-if you still foolishly want to. When you flop in opera, you can turn to law, instead of going on welfare."