u/IonicPenguin

My dad has mild to moderate dementia from a motorcycle crash 25 years ago and lives in a nursing home. He loves to read so I bought him a kindle kids so he could read and watch videos.
My mum connected his kindle to her kindle unlimited account and somehow he is now able to purchase books on the kindle (or my mum thinks he is).
How do I stop his ability to purchase books? There used to be a parents app that would allow me to see what he is trying to do but that no longer exists.
Any help would be appreciated.