hey anon sorry to hear that. look into a hair mineral analysis test (this can show heavy metals in the body which may be causing the ms) a friend of mine was able to stop her ms progressing by having a a clean diet alone. look for clues on google with the search term Healing Multiple Sclerosis - Medical Medium, etc there's so much out there just piecing it together is the hard part.
hopefully you find someone who knows what the fuck they are doing and can help your son heal