Aside from the food & drink thing*, your son kind of sounds like me. I have special protective equipment for mine as well, and I wouldn't let anyone else handle it for more than 2 minutes while I was watching anxiously over their shoulder even if I trusted them otherwise.
Well, maybe in a few more years he'll want to upgrade and you might get his as a hand-me-down the way I got my dad's old Windows netbook. They are pretty pricey† to begin with, but they really do have a lot of nifty stuff included right in the system (and the past couple of OS X upgrades have been completely free).
* I do eat non-spattering food in front of my Mac, situated well away, and with a paper towel positioned on top of the keyboard, just in case.
† The stats are that most Mac users keep using their Macs for 5 years, in comparison to the standard 3 for a Windows PC. The joke is that after you've bought a Mac, you can't afford another computer for another 5 years…