I'm so sorry for your sister as well as you and your family. This must be so scary for you all. I would definitely discuss this with her dr(s) as a number of other conditions could cause this as well as, on a rare occasion, MS. It is so important for her well being that this be addressed as soon as possible.

Is she home by herself at all? I would be concerned about making her phone so that she can't call out as an emergency may occur and she can't call anyone. Does her provider offer an option where she can only call certain numbers such as yours, her doctors, and/or emergency services? That may be a better option.

I will keep you all in my prayers and I hope her surgery goes well and she has a speedy recovery.