I know some hotels think by just having grab bars that it is handicapped accessible but that is not enough fo us.
Hotels have 2 types of handicapped accessible rooms.
One type is handicapped accessible and is the kind that would have grab bars, but may not have room in the bathroom at all for a wheelchair. That kind of room would also have grab bars by the bathroom. Those rooms would be useful for someone who is able to walk, but needs grab bars to maintain their balance or to pull themself up.
The other type of handicapped rooms are fully wheelchair accessible. Those rooms have a bathroom that is arranged to have a wheelchair space next to the toilet. They also have a shower with a flat entrance that can have a shower chair rolled right in (that is called a roll in shower). Those showers also have a bench seat built in that can be folded down for sitting on; some people are able to transfer from their wheelchair to the bench for showering.
The bathroom also includes a roll under sink that can be used while sitting in a wheelchair. THose are fully wheelchair accessible rooms.
ALL WDW resorts have both type of handicapped accessible rooms, you just have to make sure you make his needs known when making the reservation. If you check out the disABILITIES FAQs thread near the top of the thread list, you will find information about the different types of rooms and how to reserve what you need.
All hotels are required to provide handicapped accessible rooms, although some older hotels don´t have as good of accomodation as newer ones. I am not home right now and don´t have access to all the links on my computer, but I can tell you that there are specific requirements in the ADA about the type and number of handicapped accessible rooms resorts have available. Since AKV is just being completed, their rooms would be required to comply with standards that should meet his needs very well.
On my home computer, I have pictures of the fully wheelchair accessible rooms with roll in showers at SSR, which are a similar plan to the AKV rooms.