I advise doing what the others said. Encourage him and have fun and don’t worry about whether or not a game gets made. When he’s playing games, you might point out how you think the developer implemented things (even simple things).

I got into coding when I was 13. The only game I ever really made was a top down shooter with SML because I 1) learned that games are hard work 2) had no idea where to get assets besides ripping sprite sheets which I didn’t have the attention span for 3) I found more joy in the coding itself than making a game. I always had some dinky project going and it was almost never a game. Hell, I had more fun making a GameBoy emulator than making games!

These days, now that I know what I’m doing, I have an idea for a game I’d like to make. I wonder if I’ll ever get around to it? It’s ambitious, but I think doable solo (minus the art). It’d probably be a 5-10 year project. A big part of the reason I haven’t started it is I know how much not fun parts there are involved, like tuning algorithms.