You could easy make a mount for the chair. Even one if these You could get the focus one and make a longer handle for it that also reaches down, again so he does not have to lift his arms. Just mount it to the armrest and use it that way. Also you could get (if they have it) a shutter release for the camera. So he could release it while his hands are in his lap. This is close to my heart as I also have a friend that is handicapped. I am one of his (caregivers) We are constantly trying to find stuff like this. He just lacks the fine motor skill for this application.