Jimson
I showed your son how to change a tire on the DT1 at one of the CD's a several of years ago. Buy him the tire levers ($20) and let him go for it!
When he's has had plenty of practice and gets the job down to 10 minutes off and on the bike, that's when you'll start making money out of him! Next time we catch up I'll show you as well. Practice Practice Practice!!!! Then it becomes easy.......
Tubes are cheap, times the costly item in life!
Peter B