I don't have a son w/any health issues at the moment but I want to send you encouragement and support nonetheless.
I know its hard when there is something wrong w/our kids, esp when you see other mamas out there running around w/their healthy kids.
My baby was born 2 months premature. I had to live in agony the whole time seeing other moms cuddling their babies at the store, church or in the neighborhood while my baby was all tubed/hooked/venhilated up in some incubator at the hospital not knowing if he was going to die on any given day. I couldn't even hold him. I just had to watch him through the glass cover and if I wanted to touch him I had to use the gloves that were attached to the cover. So, I kind of know the isolation you are feeling.
Can you try calling up your local hospitals or even the nearest children's hospital and find out what services they offer to support families dealing with their child's illnessess? I know the one here in Houston offers something like weekly/monthly get togethers for families with children of long term illnesses. Also, there should be a Ronald McDonald house around. Their main purpose of existence is to offer support services to families dealing w/their child's illness, short or long term. Try and see ifyou can find moms there you can talk to.
Peace and prayers to you and your son's journey.