I am looking for good options for an elderly relative which has some onset of slight dementia, but is still living alone (with assistance).

The main problem is that usual things are becoming just too complicated for that person. There are too many details that don’t matter. For example, user interfaces have a lot of features that are not strictly needed, many hidden states, often no clearly visible affordances, and so on. Some mail clients make it difficult to recognize phishing.

As a good example how it is done better, I’d name GNOME simple-scan. A really good and simple UI!

This person is currently using Thunderbird + Firefox on Windows, and K9 Mail on Android. Learned to use Windows in their sixties and is now in mid-eighties age.

The main need is a simpler Email client.

Any suggestions?