I would put a wide satin binding on it since he likes the feel of satin. Walmart used to carry them, I don't know if they still do but they should be available in any LQS.
Children like that can sure tug at you heart can't they? We have a little girl with Downs Syndrome in our church and although she can be a pistol at times she's still my little sweetheart. She seems to like tiny things so I took some fabric that had little 2-3" paper dolls on it, stiffened them and their dresses and made "church dolls" for her. The dolls, dresses, and accessories all fit into an Altoid box that I carry in my purse. When she sits with me she points at my purse to let me know that she wants to play with them.