By all means start with a clean install (format & install). I've done the upgrade thing a few times and the resulting install seems to always be more "glitchy" than a fresh install (especially going from the 98 kernel to an NT based kernel). I ended up reinstalling every 3 to 4 months as opposed to the 1 year my current install has been running. I install a ton of software to evaluate (as everyone here probably does) and all of the installing/uninstalling plays havoc on the file system and registry. Besides, as you said, he doesn't ahve any data loss to worry about.
You probably know this, but just make sure his system specs are up to snuff. 256+mb of RAM, decenet HDD (the faster the better), at least 1Ghz of processor power...stuff like that.
Hopes this helps.
AMD AthlonXP1800+(OC'd to 2000+)/Soyo K7V Dragon Plus!/512mb Samsung PC2100 DDR/(2) Maxtor 60GB 7200rpm HDD striped w/ onboard IDE Raid/Sony DRU-500A(replaced w/ TDK 840G)/Pioneer DVD-105/Radeon 7500 (64mb)..and a S.S. Directron case.