This will probably sound crazy... but reading recent posts I remembered something from a few years ago. I don't know what all of his symptoms were, but a good friend of my parents became really sick quite suddenly. He had to leave his work, he had to use a cane, and I remember him barely being able to hobble up my parents driveway he was so weak. He was getting worse and worse.
Today he is 100%... guess what it was... he was allergic to their new dog!! I couldn't believe it... they got rid of the dog and no problems since. I had no idea a bad allergic reaction could do that.
I'm not saying anyone's problems are this... I just thought maybe it was worth pointing out.