It'll ask you to register the iPod when you first use it, requiring him to get an appleID. He can do this from any computer though, it doesn't really matter.
The iPod will sync with the music on iTunes. If he syncs it with your iTunes library, then when he goes to sync it with his it'll ask if he wants to change the association over from yours to his. Saying yes may erase everything on the iPod if he doesn't yet have music in his iTunes library. To get past this you can use yamipod to copy the music from iPod to his computer first.