IVIG works for some in that they feel great for a week until the next infusion. I was doing IVIG other week for five years with no results. I finally told them I was quitting it was a waste of my two days a month. It’s so rare… is your son a child or adult? I’ve had it for 15 years. I see the first certified specialist in the world in Phoenix Arizona. I got very lucky. However even he hasn’t had many answers other than treat the symptoms. I have been on Vimpat forever & it make a difference. There are so many symptoms that are individual to each person with this disease that often doctor say they’ve not ever heard of that. And yet I find it in other groups that other people have the same things I do so it’s a crap disease. I don’t know if any of this is helpful but you can certainly hit me back