My daughter's DH has MS and it's getting a little worse each year.
I'm told he was born way too early, got a bad start in life but he refused to admit for many years that he was handicapped. Held down a demanding security job till his body forced him to quit.
He was delighted to get my own DH's electric wheel chair so he can visit his mother across the street while my DD is at work.
No one has been able to tell him what caused it or what will cure it or what might even help, besides a good diet.