Ohgosh, that's so sad. I think one of the hardest things is watching someone have to give up the things that motivated, inspired and drove them. Pottery for your mother clearly seemed a passion. I'm sure she's said goodbye to it on her own terms, but that doesn't make it easier. For me, it's surfing - I am aware my time is running out. Who am I without that? I know I am many things, but ...
My father is an inspiration for how to adapt despite illness - he took up photography when he couldn't kiteboard any longer.
Yes, I believe she has said goodbye on her terms and now seems like the right time for her. She wasn't ready before.
Although leaving surfing someday will not be easy, you will move forward with the many other facets that are in you. For sure.
Have a lovely weekend:)