Having a respite of 5 months does not mean that your husband's MS type has changed. I have had progressive MS for 35 years. I would only encourage you to lay aside your fears because you will go through good days and bad days, BUT every day will bring blessings.
No MSer has any way of knowing how or what their future will become. My disability did not come for 20 years (25 from onset). Other MSers may have a shorter time to disability. Also, there is no way of knowing to what degree one will be disabled.
Your worries and fear can affect your husband. You need to calm yourself. If your husband is fine, you need to be as well. If you have to vent, please vent here but remain strong and steady when you are with your husband. MS is not something to fear. You are in my prayers.