Hi, is good to see a family member who is trying to help instead of malign the person with MG. So many folks have just the opposite, sadly.
Being informed is wonderful.
As to the medications that are commonly used, there is a website MGFA that will tell you all about the mainstays for treating mg. Why each one is used or not used. The possible good vs bad effects of each.
As to what treatments each of us gets, it is very much individualized. Some get by with mestinon alone. Some get by with a combo. And then other hard headed MGers, such as myself like to have a nice salad bar type variety of medications/treatments to get by. sigh. LOL I have been on pred for about 5 years now. 60 mg a day. And have all the bad side effects to show for it. We have tried numerous times to wean off of it, but my body is very resitstant to giving it up. Currently have been at 50mg for a bit over a month now. ACtually doing OK. Of course we increased the IVIG from biweekly to weekly to help with the weaning.
So again, keep investigating things. Learn as much as you can so you can help educate your family and sis in the MG journey that is just beginning!