I read your question and I am sorry about your husbands issues.
However you must understand that multiple
sclerosis is a chronic disease meaning there are no treatments to cure it only slow it down. After periods of relapse (a worsening period with new deficits due to new lesions) there can be partial improvement but however some degree of impairment remains like in the case of your husband. With new lesions adding to previous ones in time
disability might progress although many patients live a good quality life for many years.
Treatment with Avonex is not aimed at making the present symptoms disappear but at slowing disease progressions and lowering relapse frequency. There are other treatments for accompanying symptoms like
fatigue or possible
depression (perhaps among the tablets you mention), but they are aimed at easing the symptoms, unfortunately not always able to make them disappear.
So while you should discuss your concerns with your
neurologist so that he can add these additional treatments if not already given, you should be patient and prepared for the eventuality of the symptoms persisting to some point.
Hope to have been of some help. Feel free to ask further questions.