Since you want to do a lot of diving, Bonaire
might be a better choice. The dive sites in some areas are back to back, some as close as several hundred yards apart. On Curacao switching dive sites usually requires a short drive back out to the main road then back in at the next location. We easily managed 4dives/day on Bonaire just about every day we tried. On Curacao it was only possible to do that twice - except for the days we dove at night.
The diving is almost the same at either location - it's the same reef. Same fish, seahorses, frogfish, turtles were often spotted at either location. IMO the diving is more varied on Curacao, there's some vertical walls in places, the Mushroom Forest etc. After about a week of diving Bonaire my buddy turned to me after one dive and said "same dive, different location". I agreed it was all starting to blend together by then.
Navigation is relatively easy off either island as the reef parallels the shore. And the water is typically so clear that you'll see the marker ball - or the rope a long way off. Just notice the direction the current is flowing (if any) and swim into it to start the dive. Off Bonaire the far south sites past Red Beryl can be advanced dives - esp. in the afternoon. Once the current was ripping off Vista Blue - laid the fans down flat against the bottom. Some of the far north sites in Slagbaai park are also. In a week of diving off Curacao we only dove 3-4 sites that had any current at all - and it was easy to manage.
But the reef starts further out off Curacao. At many Bonaire sites you'll easily see the mooring ball just offshore, at some Curacao sites you have to swim out off the beach a short distance - usually on the surface to save air.
The downside is that most of the Bonaire entries are over ironshore and coral rubble - often hidden in the surf line - not sure if that would be a problem for your son. Good treaded boots are a requirement. Get a much better idea of the differences here - most site descriptions show the entries.
Scuba Shore Diving Region: ABC Islands
Many dive sites on Curacao have some sort of facility on-site also. At least a snack shop and many also have tanks and weights. On Bonaire the only dive sites with facilities are the dozen or so dive resorts - many of which are on very good named dive sites also. Most of the sites either north or south of town don't have any facilities. And it's suggested you not leave anything of value in the truck. One other difference - esp. if you want to do some boat divng - is that Klein Bonaire is a 15min. ride, Klein Curacao is an all day trip.
If you do go to Bonaire diving the resorts as suggested above is a good idea to start off. It will get you familiarized with what to expect. Actually one of the best dives on Bonaire is Bari Reef - located between Den Laman and Sand Dollar Condos. It's shallow, a simple entry off their dock and has the most counted species of fish in the Caribbean. Capt' Don's Habitat has access to 2 sites off their dive dock, Cliff and LaMachaca. The best part of Cliff is a short swim north though. Buddy Dive's reef is also supposed to be good, I've never dove it.
