P.S.
I might also add that, in my opinion, the very best thing a person can do for MS (or any other medical condition...) is try to optimize one's overall health with a healthy diet (I don't believe in any specific MS diets...), plenty of exercise, & plenty of sleep. And I've found that my absurd sense of humor has been helpful as well.
I'm sorry if my med post above made it seem hopeless, because I don't feel that way at all. My story is that, after years of weird, MS-type experiences (that I attributed to childhood whiplash incidents and injuries), I decided to make it easier on myself and get my body healthier. I cut sugary, greasy, crappy food out of my diet, added daily exercise, lost weight, and got so healthy after about 15-20 years of that approach that the day I was diagnosed with MS (at age 52) I was feeling stronger/healthier than ever. And it's likely I had MS from at least age 23 -- or maybe even childhood (plus other medical conditions). I know you're concerned about your son, who is also in his twenties, right?
At my dx there seemed no reason whatsoever to bombard myself with drugs after all that time. I feel very fortunate no one ever told me I had MS all those years ago so that I was forced to adopt my healthy lifestyle, which is what made having it so much more bearable. I also have managed to go to physical therapy almost every year since my diagnosis , and they've taught me things that I've incorporated into my own routines.
Another note: I caution people about bombarding themselves with vitamins & supplements, which are NOT totally harmless, no matter what anyone here says. I have personally had more serious side effects from some vitamins & supplements than anything MS has ever done to me!!! Even the ones most often recognized as helpful for MS. (Omega-3s, especially, also vitamin B-12, C, D)
I wish you and your son well!