I found a solution...
That's Webmail by Westhost. It's Web-based Email. It has such a simple user interface and it never changes. It will enable me to write some simple procedures that an elderly person can follow. It's perfect. Sometimes less is best.
I've come to the conclusion that there are no Email client apps that you can install to your home computer to be used for a POP Email account that are as simple as this WebMail program.
CONS: Anyone else looking for a similar solution will not be able to use WebMail unless they have a domain at WestHost webhosting service.