Lol yeah sisters can certainly be that way, my sister and I can be polite in society but both of us are happiest keeping half the country between us and a convenient lack of memory for phone numbers . Another approach you might try with her is the tough love way... put her in charge of her own health. She says the doctors won’t operate (which yeah they probably won’t) so basically demand from her what’s next? PT? Cortisone shots? Implant pump or tens? Medication? Make her look it up, make her own choices and tell her your kids aren’t going to go over there and pick her up off the floor if she’s just going to wallow in her self pity. If she’s anything like my sister I’m sure it could be one heck of a row (she did not like the tough love approach to her husband cheating on her)

Basically need to get her to realize there are options, but you’re not gonna find them just bemoaning that one avenue that was closed. And doctors do care about their patients, but with all the specialists out there, they rarely have access to all the treatment options even more so if the patient doesn’t pretty much demand from their doctors the “so what now? And where do I go from here.”