What a roller coaster ride! I think I'd be looking for a med center that specializes in this sort of thing. Maybe Mayo Clinic or Johns Hopkins or MD Anderson. Often these places know treatments that are not generally available and how to get signed on for them. It sounds like you have the time to research it and talk to people, but I would definitely get a second opinion in a place that has more extensive experience in this specific problem. I know it sounds scary to travel or to start over, but I have seen that be the answer.
I'm not sure where you are, but maybe there is a major med center not too terribly far from you. I'm praying that you connect with the right people quickly. I don't see how he can live a normal life the way it is. I would not accept that without a fight.
I am so sorry for all of the stress and turmoil that you are going through. I know how the medical system can make you feel vulnerable and helpless, and afraid to demand answers. I have been there with a sick child. I will never allow myself to surrender control again. (My story had a happy ending, but was terrible to live through). I will always seek medical professionals who will respect my right to make knowledgeable choices, and will help me do that. Most doctors, in this type of serious condition, are happy to have you seek a second opinion.
Keep "talking" to us! We care!
Joy