Susan,
If anyone solved the MS fatigue problem, you would hear an MS cheer around the world. In the MS support group I went to, it was acknowledged as the worst of all symptoms, even the guy in the wheelchair thought so. I took Amantadine too but it had little effect on me. I have also taken ritalin , and now I take Strattera, it has the same type effect as ritalin, but is non narcotic. It changes the mix of neurochemicals in the brain. It is also smoother, without the jitters of ritalin and one pill works for the entire day. In my case it also clears up the brain fog which I greatly appreciate.
In a lot of ways, the first days of MS are almost the hardest. And I sympathize with your husband. I too was very healthy when it hit me in my late 50's.
Actually, I hate to mention it, but at your husband's age he is considered too old to get MS, just like I was.
If he has other indicators pointing away from MS, like a clean spinal tap, he might want to get a second opinion at an MS specialty clinic...but, be warned, the alternatives to MS, the other white matter diseases, are almost worse than MS. They are usually fatal, and they have no treatments. On the positive side, though, they are usually very slow moving so the fatality only applies to the younger people who get them, and not having a treatment makes life so much simpler, there are no worries about what you're taking and whether it works or not. Good luck to you. P.S. You should go with your husband to a MS support group in your area.