I'm not much help here, just support!
A hug and a shoulder for all you and hubby are going through. To answer one of your questions I've not heard of MS lesions going away. Normally they scar up; hence the name Sclerosis. Many Scars. Mighty Scary, for some people!
Has hubby had bloodwork to rule out MS mimics? A lot of diseases resemble MS in symptoms.
I hope you get some real answers soon so hubbs can get on the proper treatment!