Being PA is quite possibly my mother's favorite hobby. If we try to give her what she "wants", that just fans the flames. Once, a bunch of us were going somewhere and taking multiple cars. Well, she wanted to ride in my car, but I guess just expected the rest of us to figure this out via ESP. When she realized she wasn't riding in my car, she was all "fine, I guess I'll just stay here then" etc. We said okay and left. Since the silent treatment is her second favorite hobby, the family was subjected to that for a few weeks after that. I tire of giving her what she "wants" when I know it will ensure silent treatment fits for days, weeks, months.
This year, I hit upon a new plan. Just act like everything is normal. Usually her PA comes out in the form of massive hissy fits like you would expect from a toddler. So now, that's what we do. We just keep acting like everything's totally normal and that my mother has not, once again, regressed to childhood. Doesn't matter if she's throwing her fits at a restaurant, in the car, when I'm visiting her, whatever. She still hasn't found a new hobby, but at least the rest of us no longer want to take up drinking.