My Son was dx at 9. Right about the time that sleepovers were starting. The invites stopped. Not even birthday party invites anymore. One of his best friends even told him "my Mom didn't want me to invite you". Nice job Mom. Thanks. This really breaks my heart. He never complains. I know he know why. Do you have a special way to make your child feel better when this happens?
The one friend's mom isn't cool, but that doesn't mean that the parents of your son's other friends feel the same way. Have you had a sleepover at your house? Do that and then the hospitality will probably be returned to your son.
My situation was a little different because I was diagnosed before starting kindergarten, so I was always the diabetic kid at school. But I went to plenty of sleepovers and the parents never made a big deal of it. They just assumed I'd take care of myself and let them know if I needed something.
I'm sorry to hear that your son has had to face something like that. I have not let my daughter have any sleep overs other then families house. I just couldn't handle the stress I wouldn't have been able to sleep. She is okay with that since we are all very close and have a very large family. I think jennagrants idea is great, maybe she host the sleep overs yourself. That way you don't have to worry and he can still have a good time with his friends.