You never need a CD to play FFXI- once its installed it'll run with or without the CD. Basically, once you've installed it on his machine he can play for 30 days. If he or she wants to keep playing after that they'll need to buy their own copy and register for a full account, as opposed to a buddy pass. Im not certain, but I think they might be able to carry over the same character they used in the 30 days. Might be worth looking into that.