Welcome to this awesome group that no one wants to join but are so very glad the can. I'm sorry you needed to find us, but you will be glad you did as the support and information you will get is amazing. Unless you have been confronted with this awful disease, others just can not truly relate or understand. I am so sorry your sister has been cursed with this disease and that you and the rest of the family also have to deal with the reality of it all.
My husband died almost 9 years ago after only 2 months of illness and only 10 days after being definitively diagnosed, so I really can't be of much help as far as suggestions or treatments as we didn't really have enough time to even deal with any of that. I do know that things have changed a lot since then and there is much more knowledge and more options then there were back then.
It sounds like you have already gotten more than one opinion, but if not, 2nd or 3rd opinions can be helpful. Try to be cautiously optimistic as one never knows how things will go. No matter what direction her treatment goes in, the most important thing to me has always been that the patient be kept as comfortable and pain free as possible.
I'm hoping others will chime in soon with some suggestions and advice as to treatments etc.
Try to take some time out for yourself and your family when you can. My thoughts are with you all. Know that you have a lot of people here willing to help and support you in any way that we can.