You asked.
For the low price ($200-250), I think the Nook/Kindle Fire may be what you want. It can easily and quickly send and receive email. Not knowing her eyesight, the ability to read books in LARGE text, and various fonts - may be something she would really like.
The iPad is my particular favorite; very easy to use, can easily make text larger - with the 10in screen, it can display more of a large text than the smaller Kindle/Nook can with it’s 7inch screen. iPad will run more money, in the neighborhood of $600 for one I would consider (16 Gig is just too small for full utilization).
Kindle Fire and Android sound promising.