How to monitor elderly parent with dementia using parental controls or . . . how?

My mother has been the victim of financial fraud and I need to be able to block her access to downloading What's App, and perhaps some other features of her iPhone, iPad and iMac. Can parental controls or some other system be used to alert me to when a new app is downloaded, or otherwise be updated on her activity? She is willing to have something like this set up as she wants to be able to use her devices and be online for a lot of good things, which I want her to be able to do. But I need to have some protections/monitoring in place . . .