I had problems for awhile getting my blade up above the water when setting up for a c2c. I spent a couple roll sessions in the pool using a paddle condom- a piece of closed cell foam folded over and ducktaped. This slips over the blade of the paddle and really helps one to get the blade up and parallel to the surface. Then you go to the pool and roll, roll, roll, roll, roll, roll. You end up gaining: some confidence and "muscle memory" so that when you take off the Condom, the roll is easier.
This isn't a fix all, but is a good transition step between practicing hip snaps off the side or using a pfd to an unaided roll.
However, in my mind, the combat roll is about 85% psychological and 15% technique. You need to take a "proverbial" breath when upside down...that 1-2 seconds keeps you from rushing the roll and missing.
But I agree, if he isn't even trying, tell him to buy a duckie....there is no shame in that.