I have a 16-year-old son. I’m in my early 30s (had him very young) and a professional footballer. My son also dreams of becoming a successful footballer (he’s been playing since he was 6), but he’s just… not great. He’s good, but not great - and in this extremely competitive industry you need to be at least great in order to even stand a chance. So I told him, as someone who’s been doing this for a very, very long time & is active in this sphere, that he should find another, more attainable dream. He took it as me not believing in him, but I’m just objective and realistic.
If you’re a pro, then you know coaches.
Coaches who you could engage on friendly terms to say “Hey, can you coach my kid? And if needs be, let him down gently?” - see what they think of his potential, and if they need to be the one to tell him he is unlikely to make it, then it’s going to be easier coming from then than from his own Dad. You get to look like you’re backing him by sending him to “one of the best coaches in the business” and then console him when they deliver the rough news…