The free sample is good reading and makes me want to read more. However Amazon has only made the book available as a free Kindle download (to Kindle devices) or as a $$$ paperback. As author, can you ask Amazon to make the book available as a downloadable PDF?
Does your aunt or f-i-l really need to know? I know older nerds who only use a smartphone for texts and voice calls, and who can't be bothered wasting time on social media. So far (anyway) "essential" apps like banking ones and government ones and "remotely check your home security cameras/solar panel output/etc" ones seem to be paralleled on the Web and accessible through a browser.
"The look on the faces of a fresh crop of 20-something developers"... My equivalent is doing a data reformat or analysis on a big dataset that someone has been struggling with in (please excuse my language) Excel. The data owner's eyes widen and they say something like "Wow! That's so fast and simple! How come I never heard of this stuff?"
Good question about "Old". In Australia there's at least one well-defined cut-off: 75 years. If you're 75 or older:
- when you die your death isn't classed as "premature", and demographers don't assign you any "potential years of life lost"
- you're no longer invited to have screening for bowel, breast or cervical cancer screening (invites go to 50-74 year-olds)