Thanks, everyone. It's one of those ones that's not surprising, given all her health problems, but also unexpected because it's not like it was some consistent downhill slide. If a cat has 9 lives, I think given all her issues she was on her twelfth...
My older sister is heading to CO to be with my dad right now as she has a lot more schedule flexibility than the rest of us, and then we'll be out there whenever this all gets arranged.