Like Lisa said, a lot will depend on whether he is able to get out of the wheelchair and walk a few steps. If he can, he will basically be able to go on any rides. Wheelchair users generally wait in the same lines as everyone else. For some rides, your party will board at the exit. If he gets out of the wheelchair, he can drive it right up close to the ride car. His wheelchair will be waiting for him at the exit when he gets out of the ride.
For some rides, he cans stay in the wheelchair thru the line and the whole ride/attraction.
Here's a link to the DIS page about touring with a wheelchair. If you scroll all the way to the bottom, you will find a list of rides where you can stay in a wheelchair and rides where you need to transfer out.
Each park has a Guidebook for Guests with Disabilities that has basic (very basic) information about each ride. If you go to the
official Disney website you can get the same information. The Disney site won't let me link to the page you need, but here's how to get there: Follow the link to the Disney page, then click on the WDW icon. The next page you get to will have an icon for each park. When you get to the page for a park, the boarding information is under the link to
List of Attractions.
