[asphaltgambler]

From experience, as long he's into it and you show interest as well joining him, it may last awhile even at his age. When / if he loses interest it will be very apparent.

For me personally, I got into scale Planes in 1985 when I saw a local guy hosting a club with flying events. He also ran a hobby shop out of his basement. I went to a few demonstrations, was immediately hooked. I bought a glider kit with an electric motor / prop. It was a semi component not a stick / piece by piece construction. I assembled it learned how to taxi, fly and glide, then moved to gas scale Cessna high wing which I crashed more times than a demolition derby car.

After some time and a fair bit of money, I could usually take-off, fly and land in 1 piece. But that's when the whole thing got kinda smooth. There was no (obviously) sensation when flying to me other than accomplishment of doing so. Sorta like a 3 dimensional video game.

The initial enjoyment was spending money (on something ridiculous), assembling the aircraft and fine-tuning the electronics. So after @ 1-1/2 years in, I sold everything and haven't looked back at all.

Did I enjoy it, was it worth it = YES! Would I do it again = Probably not. It's a hobby that I looked at from afar as a kid, then got to experience as an adult.