HAve him tested for Lyme. I was sufferening from Neuropathy In my left eye and in both of my feet. One blood sraw and a test from Ingenex later, I not only had Lyme, But Erhlicia, BArtonella and Babeosis. Been on IV meds for the last 6 weeks. My vision has returned and my feet only hurt some of the time. Still have a long way to go, but it’s doable.
Seriously, at least humor the lyme thing.
Good heavens, I'm almost embarrassed mentioning my husband's condition considering what you're going through. Prayers, and best wishes for a full recovery to you. Oh, and yes, I'll remind him of the Lyme possibility.