There are also notifications from iPhone/Apple that her iCloud storage is full, thus uncapable of backing up, which bothers her even though she claims not to understand what that is or what it means.
Her cloud storage may indeed be full but be aware there are a lot of scams that start by reporting this. For the last few weeks I get daily scam emails saying my cloud storage is full etc.
We have looked in her settings on iphone several times over the year and found the 5GB is indeed full. When we’ve tried setting up extra storage in the past there is always a roadblock, be it lack of email or lack of credit card or lack of patience on her part. So that’s another factor in solving this.