Honesty, I think the best choice for an elderly person for a tablet is the Kindle Fire HD models. You can choose from the 7 inch screen or the 8.9 inch screen. It is my thinking that the 8.9 inch model is best for older people because it has a larger screen for them to view items but the 7 inch is perfectly OK.
The reason that I recommend that this is the tablet best suited for senior citizens is that it has everything that they will want and is easy to use. It's also a very good price/quality buy.
They can access millions of book titles to read without having to worry about storing hardcover books or paperback books anywhere. They can try free samples of books before they buy them and they can adjust the text so that it is easier for them to read the book of their choice.
If they happen to like to listen to music there are also millions of tunes for them to choose from. Along with movies that they might like to watch.
They can also retrieve and answer emails or enjoy a Skype call. Just imagine the joy of them getting to see and talk to a family member that lives too far away to come for a visit.
You can send them pictures that they can easily access anytime they would like to see them. One drawback is that the camera is in the front so unless they want to take a picture of themselves to send it might be more difficult for them to take pictures. It is not impossible, just that they will not be able to see what they are aiming at if they turn the camera to take a shot. Honestly, though they probably won't be taking many pictures, they will just like getting the photos.
The Kindle Fire HD's can be easily connected to wi-fi if the facility where they live has it and most do these days. Or you can set up a local network in their home for them to be able to access the internet when they want to.
Tablets are lightweight and easy for them to carry to enjoy in a chair, on a sofa or even in bed. If they are wheelchair bound a tablet like this is perfect and better than a laptop because they can easily hold it in their hands or sit it on their lap.