God bless the support dudes, seriously. We always treated our mechanics as well as we could (especially when we knew we would be going to other FOBs w/ big PX's, we'd get a shopping list from a select few of them).
BUT, and this is a big but, a support role is 100% unsat for anyone who wants to be a combat arms.
I realize the Marines like to tout the "every Marine a rifleman" line, but let's be honest: combat arms is combat arms, and nothing else is.
The way I always looked at it was if you're going to do something you can do on the outside, there's no point in being in the military -- especially if it's something you can do without .mil experience. Which is exactly why when they offered me a choice between med retirement and a list of support MOS's, I chose retirement.
Hopefully the kid makes the right decision for himself and is willing to live with the reality of turning wrenches for 4 years.