How about taking the PADI Advanced course? This gives you 5 more dives each a little different with an instructor. A Deep dive, Navigation, plus 3 others (my shop usuallly does Night, Buoyancy and Wreck)
In total it more than doubles your ocean dive experience. A good instructor will tailor the dives to what you need. We tend to throw bouyancy drills into most of the dives. "while staying exactly level with a spot on the hull of the wreck point out hazards to avoid'
Also look at guided dives in a small group of 1 - 3 diver with a DM or instructor.
Good Luck and don't give up!
The worst thing he could do. If he's not comfortable out of the OW class, he should go back and demand he gets what he paid for. Not take another class that will cost him more money and leads to more frustration.
No one should sign up for an AOW class unless they have their basic skills down and can perform them neutral and in trim. Every one of my OW students can do this out of the OW class or they don't get a card until we figure out why.
By RSTC standards an OW diver should be able to plan, execute, and safely return from a dive with a buddy of equal training and experience with no professional present.
A good instructor will refuse to sell an AOW course to someone who is still nervous out of the OW class. He will instead offer more pool time, offer to allow the student to come on dives within the level of their training and experience, and maybe go for a fun dive or two without expecting to be paid. Not try to get more money from them.
Every student of mine is welcome to come on any dive I am doing that they are qualified for. If I have students they can tag along or be a buddy to one of the students if the student doesn't have one. I don't charge them for that. They pay the entry fee and supply their gear.
I don't sign people up for another course. Even if they are spot on, I want them to get some dives in outside of a course before taking another one. Let them practice what they have just learned before throwing more at them.