I am so happy for you and your family. One of my riding buds is now on his second kidney transplant (along with a pancreas transplant) and riding strong. When he was between kidneys he would still bike tour, by riding from dialysis center to dialysis center. His story is here, perhaps your son will enjoy reading it, its quite inspiring: http://www.bikefriday.com/tedcampbell
Good luck to your entire family!!!!!!!!!!