AustenNut has it right. How does your son see himself becoming an independent, self-supporting human being?
Even if he sees himself as a creative artist, he probably would need to earn a living somehow other than selling his art. The first question is not “what do you want to major in”, but rather “how can you do something that makes you happy while also solving the issue of becoming financially independent of your parents”. The list above is a great place to start a conversation. After that comes the where to apply conversation, based upon interests, majors, and finances.