When I was a youngster, my oldedr brothers mtaught me how to make ma "tank" from a cotton reel, a matchstick, a panel pin and a rubber nand.
later I was taught how to solder, to make a simple steam turbine form a syrup tin, a Meccano shaft and some other bits of tin. Mounted on the cooker, it ran well,, until the water had all been used up!
These might binterest him, although the soldering and running may need some supervision.
Howard