Cass:
You didn't mention your budget, so I'll give you a few suggestions across the dollar spectrum!
Value: All-Star Movies. Most of the icons (especially Buzz Lightyear and Woody) will be recognizable to your son. In fact, when my children stayed there, they spent more time wanting pictures with the big statues outside our hotel room than with the characters in the parks! Rooms are small, but there's just three of you!
Moderate: Caribbean Beach Resort. Only if you get a pirate room! You'll walk the plank as you enter the room, stepping on carpet that looks like wood and then you'll notice the beds are in the shape of boats! If the weather is warm, plan on spending some time at the well-themed pool. The water is warm, and its water play area for kids sets it apart in not only the moderate pools, but quite possibly the deluxes as well!
Semi-Deluxe: Animal Kingdom. Get a Savannah View so he can wake up and see the sight of a giraffe or zebra from his balcony! The rooms have a rather dark decor, though, which along with its bus-only transport, makes it less desirable than....
Deluxe: Polynesian. The theming, the monorail, the erupting volcano at the pool, its large rooms and distinctive restaurants add up to why it's a perennial favorite, but also a large price tag.
Wishing y'all a magical vacation!
Whitney