There really isn’t anything like a magic list for your friend to tick off. The big problem with MS is that we all experience MS really very differently, so what I might ask won’t be what your friend needs to know.
It’s more about having a conversation about your friends symptoms and variety of MS. Some of this s/he will perhaps know or guess already, ie what variety of MS do they have? (See https://www.mstrust.org.uk/about-ms/what-ms/types-ms )
Once that’s been established the question will be what disease modifying drugs are available for them? The answer to that question really initially depends on the answer to question one. If they have a pattern of relapses followed by remission, there are many DMDs available. If s/he has a progressive form of MS, there are few (in fact only one) DMD - Ocrevus.
What I’d advise would be for your friend to write a diary/timeline of what has happened up to now. This will help at the first appointment. S/he should also think about exactly what s/he needs / wants to know. Things like availability of an MS nurse, drugs for symptoms as well as prevention of relapses/progression. Also, is there a dedicated neurological physiotherapist in the area to whom a referral could be made? While writing the timeline, your friend should also keep notes of their own questions.
Someone should, if possible, go with your friend to the appointment. Their job will be to remember as much as possible. It’s too easy to leave an appointment remembering very little of what was said. So having a trustworthy companion is essential.
Your friend is fortunate to have you asking these questions, but basically they need to think about what they already know about MS, what they don’t, and what they want to know.