For good ab workouts, I like the Firm 5-day abs. You get 5 different workouts, I think they're 10-15 minutes. They're actually chunks of old Firm videos put together. The intros to them are led by a man, which he might like, since usually the Firm videos are mostly for women.
I haven't done it in a year or so, but I remember liking it.
To burn the belly fat, he's going to need to do more cardio, or eat less. The ab work won't get rid of the fat, it will just build and strengthen muscle under it.