Is there a product that will assist comfort and prevent soreness to an amputee in a wheelchair?

p.s. In addition to his EASE alternating-air cushion during the day, he uses a ROHO overlay mattress (giant pockets of air) and then we don't have to turn him during the night.

A good cushion and barrier cream, plus alternating times in the chair to take pressure off.Pay particular attention to the tailbone area and right above it as this is most vulnerable to breakdown. If you make your own cushion and can't sew a cover, I would use a pillow case that is waterproof to protect the foam, and then put a regular pillow case that you use just for the chair over the waterproof one so you can wash it.