The ship alone I think will hook him on cruising. I have not sailed on the Star 'yet' but have sailed the Grand Princess twice. If the ship doesn't hook him, the food and service will, even if he doesn't do anything but sit on the deck and read a book all day.
Best of luck to your friend, hope he books another one while he is onboard. Remind him what great deals they have for booking onboard with low deposits and extra cruise credits.
Make sure to let us all know when he returns what he thought of it PLEASE!