For the reader, I would strongly recommend a touch screen. I have arthritis in my hands. Pushing a button to turn a page quickly becomes painful and really limits how I can hold the book. With my touchscreen, a touch anyplace on the right side will turn it.
You might see if you can find a library that provides electronic books. The Philadelphia library will sell you access for $35.00. If you want to pursue library books, you need to see what format is available to you. Kindle books are available now at US libraries, but I seem to remember reading that they aren't available overseas.
Since older eyes have a harder time seeing things, I would recommend that you get a model that has lighted covers. There are also book lights that clip on to the book or the cover, but these would probably be harder for her to turn on and off and more likely to slip off. With the Sony lighted cover, you simply lift the light up and swing it in to position over the book. When finished, push it back into its holder. It does a nice job of lighting the whole page easier.
I really like how my Sonys organize books, but the Kindles have lots of fans too. These days, I think it comes down to where you want to get your books. Speaking of books, have you noticed all the ones available here at MobileRead? Just click on
this link and then click on "Full List HTML" to download a full list of all 18,000+ books available for free. These are older books out of copyright that have been proofed and formatted.
If someone has a computer to do the work, it's not that hard to move books over via cable. A reader will hold a whole library of books these days, so it's not like you'd have to do this after each book. With readers that take flash cards, such as the Sony T1, it's possible to put the books on the card at the computer and then put the card into the reader. If that carer has a computer at home and is willing, he or she could use a couple of flash cards. They would simply load the books on the card at home and take it to the patient's home periodically to swap out with the other card.
For the stand, there are cases made that are designed to prop the reader up at an angle. I don't know how much luck she'd have with one of those, especially if she's missing fine motor control to turn pages gracefully. I'm not familiar with specific stands that hang over the bed, but that sounds like it might be ideal for this person.