MS is wicked. Different for every person affected by it.
If he has been accurately diagnosed, there is a good possibility he can be not-too-bad for many years. But at some point it will catch up to him. There is no cure and very little if any relief from any medication. The myelin damage cannot be repaired. It’s like the insulation from electrical wire being stripped away, short circuiting everywhere, or infinite resistance restricting signals.
Vision problems, body temperature regulation, leg and hand weakness etc . . . Very important to have honest evaluations on a regular basis.
Wouldn’t want to be on a racetrack with him when that time comes.
My dad was diagnosed very late in life (late 40’s) but managed to overcome a few bad years. His heart attack wasn’t helpful in his 50s. Now as long as he doesn’t overwork himself and keeps out of major heat he manages. Obviously not his “young self” in his 60s but still kicking around