My parents just bought a Sony TV with it (will be delivered in a couple of days), and I'm not close enough to them to be able to go to their house and show them the ins and outs, plus I don't have any experience with it myself.
Is there a video or something out there that shows tech illiterate people the basics of it, like how to download/remove apps, how to customize the home screen, etc?
My Mom liked it when I showed her how to use google assistant and in app voice search. She was very happy to discover the wealth of Tom Jones videos on youtube. My brother hooked her up with Netflix and she was very happy about that too.
Ask your Mom what she likes and ask assistant for that content. I didn't bother teaching my Mom about apps. Too complicated.