I know there are programs out there that will allow Windows to read the Mac formatted HDDs but I don't know if that will work with iPod / iTunes, but it's worth a try. Tell your friend to search on version tracker or download.com for (I think it's called) Mac Drive. If a program like that doesn't work then he has to reformat the iPod with the Updater but that shouldn't be a problem if his music library is on the PC it will just re synch.
--Cheers