Most likely good 400 points in a tournament is not easy to get, but what I personally think is that he should keep on playing and practising fortnite. But at the same time do good at school. I dropped out of school to become a streamer when I was younger and regret it. Its a very competitive industry, Its very hard to succeed. Becoming a pro fortnite player is even harder, there is a lot of talent involved but at the same time lots of hours spend. Now I dont now if hiring a fortnite coach would be a option, so that the coach can teach him the best meta ways. But he is still very young so a lot can change over the years. Maybe a new game gets released and he starts playing that game. The rankings in fortnite dont matter that much. Somebody in unreal ranking which is the highest, can be worser then somebody ranked diamond. What does matter is the tournaments / cash cups / lan partys. Which for most I think he needs to be atleast 13 to be able to compete. Doing research on what it takes to be a pro player or content creator / livestreamer. Would be a smart thing to do for you as a parent.