I'm legally blind and font size (to me) isn't as important as "good" contrast
what windows accessibility options calls high contrast usually hurts my eyes
With a gold font on black background, I find I'm not squinting, can actually hold the ereader in my lap instead of 2 inches from nose comparing the same equivalent font size from an android tablet to my JBL
I have the Kindle dxg it sits unused, the JBL is better for me as one eye is almost totally gone the large size of the kdxg actually works against it _for me_ the constant head turning vs a smaller viewing area
plus it is MUCH heavier than say a jbl or 5-7 inch tablet (and I do 250 curls, 250 push ups daily) and it was uncomfortable when I used it
With an android tablet with something like coolreader
http://www.coolreader.org/e-index.htm installed I can go up to size 72 (or 92??) font so the SIZE is never an issue but finding that soothing good contrast might make all the difference for your mom
PLUS -> touch screen page turning, once you have that convenience of touching anywhere on the right side to go to next page (can even use nose
using a fixed button won't be the same
you might check out these threads about vision impaired readers looking for readers:
White Text on Black Background
https://www.mobileread.com/forums/showthread.php?t=90654
Ereader for sufferer of macular degeneration
https://www.mobileread.com/forums/sho...d.php?t=129345
2 many to choose from
https://www.mobileread.com/forums/sho...d.php?t=124430
Ebook reader for a visually impaired geek
https://www.mobileread.com/forums/sho...d.php?t=113414
Using my JBL as a "GPS" (low vision navigation)
https://www.mobileread.com/forums/showthread.php?t=98195
Research on ereaders from low vision point of view
https://docs.google.com/Doc?docid=0A...0em00&hl=en_US
more links from one of my pages/posts:
Shows examples of 3 different font background colors
http://www.visionaid.com/demopage/demopos5.htm
APHont™: A Font for Low Vision
http://www.aph.org/products/aphont.html
Tips for Computer Users with Low Vision
http://www.afb.org/section.asp?Secti...ocumentID=1452
Visual Disabilities
http://webaim.org/articles/visual/lowvision
Computer Technology and Accessibility for People Who are Blind or Have Low Vision
http://www.visionaware.org/accessibility_help
Low Vision FAQ
http://www.washington.edu/doit/Facul...ision_faq.html
text color to background color check tool
http://tofu.corvallis.or.us/color/
http://mrnatural3.tripod.com/tools/colorcheck.html
ereaders info
Best Ebook Reader for Low Vision
http://www.webrn-maculardegeneration...ok-reader.html
The Accessible E-reader by Clytie Siddall
http://oz-e-books.squarespace.com/ne...e-siddall.html
Intel (R) Reader for low vision/blind users
http://www.ctlcorp.com/v4/p-879-intelr-reader.aspx
BookSense text and audio book reader for Low Vision formats
http://www.gwmicro.com/BookSense/Comparison_Chart/
The free NLS Bard talking books (tape and digital)
https://nlsbard.loc.gov/ApplicationInstructions.html
If you haven't heard of it it is a nice service
There's also
Recording for the Blind & Dyslexic (RFB&D) offers an online catalog of the best audio book and audio learning opportunities on the internet.
www.rfbd.org/ (free)
For the disabled, Bookshare leverages the collections of individuals who scan books. Braille books and tools for downloading.
www.bookshare.org/ (not free, but some libraries have a small assistance program)
American Foundation for the Blind (AFB)
www.afb.org/
has forums for technology and books that might be of interest