I don't believe, for a minute, that Aspertame causes MS, but I do know that, in some people, it has side effects. For me it causes increased depression. I've learned to avoid it....much to the dismay of my diet..
There are some MSers who swear by their diet, but, of course, they still have MS. I believe their healthy diet does help them with some of their symptom relief, but like, all the other Meds we take, it's no cure.
You are a very good friend, Blessings..