I'm with M0nica.
I have looked hard and long, and nothing is as simple, or has anywhere near the size of Library that Kindle does.
Amazon does give some authors a decent boost by putting them in Kindle Unlimited, and I have found authors who would have struggled to publish under the old systems.
I also note that most of my friends who use Kindle also buy books, new & second-hand, and use their libraries - you can't keep book lovers down! I realise that doesn't apply to you mum, who wants it for ease (and it is!)
I also note that as I get older, especially if a bit under the weather, I want to find old favourites on Kindle (usually free or cheap).
Whilst I don't want to persuade you against your ethics, my personal take is that we do the best we can. And I think that at 100, you get a free pass (I'm hoping!)