Well, he hasn't said iTunes is not running, so I doubt that's the problem.
It does sound like a hard drive failure, which is how 2 of my iPods died. The tracks that it has problems with, does it just skip to the next track? One of mine started doing that, first in the middle of a couple of tracks, and eventually at the beginning of almost every track.
The other symptom that both of mine had was the hard drive would spin for a long time. I could feel it holding it in my had and hear it when I put the iPod up to my ear. The controls wouldn't respond when the hard drive was spinning either.