I don't know, but I don't belive xfce has an oem version, they simply allow anyone to install it
--even with an oem version, the new user is still on their own as far as setting up their own preferences for the desktop, session control and so on
That might or might not be too much for him
--you know his level of comfort with Linux and can make that judgement
My suggestion(s)..- Ask him what he wants as a user name
--give it a simple password or a blank, and show him how to reset hist password - For a naive user, despite the fact that xfce is quite fast and lighter weight than the standard desktops (kde or Gnome); it nevertheless sometimes requires editing text files
--not too difficult with some clear instructions
Even a simple one or two page sheet with the basic instructions would probably be good enough, and if you want you could make it a point to point out the web site and user manual or guides or tips available..
--or even a video walkthrough as might be available on youtube or some reviewer's site..
http://www.xfce.org/http://www.xfce.org/about/tour