We got my 80yo grandma a low-end android (I think it runs 3.x android?) tablet with keyboard-cover. It took some learning on her side and sometimes answering so

We got my 80yo grandma a low-end android (I think it runs 3.x android?) tablet with keyboard-cover. It took some learning on her side and sometimes answering some really confusing tech-support questions on my side (i.e. I was reading news and suddenly everything dissapeared, how do I get everything back?) She basically uses the tablet as her Hangouts machine and sometimes she reads news. She likes the keyboard-cover, as she was a touch-typist when still working 25 years ago. In your place, I would probably talk to her, if the chromebook she already has wouldn't be the best solution, re-configuring it in a way that the she wouldn't need to remember the login password and wifi-password should be doable. If she really wants a phone, I would buy something with large enough screen, sturdy, with a good grip and affordable enough to be replaced once every year. I would choose operating system I would be able to do tech support for on the phone.