I'm an Android person, but I got an iPhone 4S for her first cell phone because it was straightforward and hard to mess up.
Now there are double-secret swipes, all other kinds of anti-user "features" that almost make her cry because she can't figure out her phone anymore.
Now I am thinking about getting an Android and finding a home app ("launcher") that makes it impossible to screw things up and lock down everything else that I can.
Edit: Crap. She does have an Apple Watch that she loves though. And Apple is not only a piece of shit company about their UI, they also don't allow their watch to play nice with Android. (Except that answering a call on the watch pipes the audio to her watch and not her hearing aids. Fuck Apple.)