I would say to reach out to the medical team to discuss it could be either the illness or medications. Never can be to sure. No question is a dumb one when it comes to caring for your loved ones. I used to be a CNA years ago and part of this disease sadly is mood changes but always check with the dr to be sure.
Not speaking from educated info on MS but, my father in law has MS and had terrible bouts of being that person that you couldn't be around. He has since after medication changes and dealing with some other issues, seems to be no longer that grumpy fussbugger so much.