The neuropathy I have got much worse with the last treatment- so it’s entirely possible her feet are ok ish in high heels. Maybe she’ll change her mind about that in the future and wear wedges again.
Maybe Catherine is trying to maintain a sense of normality - for herself/ her family. With cancer you do sometimes put on a face, at least I do, because endless sympathy can be hard. It maybe just emphasises the negativity of the situation.
I dressed up really well for my nephews wedding - mid-chemo treatments and not long after surgery. New dress (flowing to hide the abdomen), beautiful long head scarf. Everyone thought I looked amazing, but didn’t see the days I spent lying in bed sleeping after chemo treatments, and the nights I spend crying with my sore feet. When neuropathy feet get cold in bed they get incredibly painful.
I actually had forgotten some of that.
So honestly- we should stop over analysing the PoW. I think she’s doing what many people with cancer do - her best to maintain a sense of normality and not give in to the stress/ sadness of having the disease.