I have found Dr. Sarah Myhill of the UK. She has an entire wiki on treating chronic fatigue syndrome and all its many manifestations.

https://www.drmyhill.co.uk/wiki/Main_Page

DH is following her protocol which is predominantly a ketogenic diet and certain supplements. We have a doctor who is running various tests, but he doesn’t want to treat DH’s condition.

“I’m not that kind of specialist.”

“Dude! No one is!”

So it’s all the better we are following Dr. Myhill’s instructions.