Environmental Traveling Companions does a lot of kayaking trips for people with physical problems. They should be able to give advice and support.

There is also a book, Canoeing and Kayaking for Persons With Physical Disabilities
by Anne Wortham Webre, et al. Amazon says that it is out of print, but a search on bookfinder.com for Webre, Anne turned up several copies for sale (albeit a bit pricy).

Good luck, and please let us know what you discover and decide.