I've had my foremerly windows ipod as mac pod for over a year now and can't imagine going back....
I have 20GB old ipod and it worked fine with windows, you can use programs like xpod to communicate with a mac formmated ipod but i haven't tried using itunes for the PC and a macformatted pod.
To answer one of your questions, yes he can restore and make it funcitonal with musicmatch and probably itunes now ...