[b20000]

Find a place that teaches shop skills? Once he has some basic skills maybe buy him some basic tools. After that you can get him a small lathe or mill and from there teach him CNC machining or woodworking.

You probably already know this but there are really advanced Lego Technics sets you can buy. The older used stuff probably is more interesting as the newer sets have probably been dumbed down since I started building Technics 35 years ago.