Personally, rather than sending him a ton of regular audio CDs, I would send a couple of data CDs and save on shipping. If you are downloading music for him from the iTunes music store they are already in a compressed format and all you have to do is change the settings in preferences>advanced>burning to data CD (from audio) and then burn the playlist as usual. This way, rather than sending him just 20 or so songs per CD, you'll be able to send a ton more.
Another option, if you are going to open the box and see if the iPod actually works before sending it to him, is to enable disk use on the iPod (I believe this option's under preferences>ipod>music). The iPod will act as an external hard disk and you'll be able to just copy the music files to a folder on the iPod so you won't need to send CDs at all.
Finally, just so you're aware, the current iPod doesn't ship with a power adapter so it might be a good idea to buy one at the same time as purchasing the iPod. It can be a pain to have to rely on computers to charge the iPod, especially when moving around.