Yes books are good gifts for parents who are readers but for those who aren't a dollar inserted in every page will make them get excited in every page.
Don't take it literally, dollar in every page means give them books that will give them idea on how to make more money or how to set up business. But as experience says books are not just the thing you must give them but also start up capital. It will be the best gift they will receive.
Insert a dollar in every page. Read enough to them so that they get excited and want to know more. Then suggest a good school where the page-money can buy them a GED, so they can learn to read.
Perhaps you can talk Alan Korwin - who is selling the books;
click the picture in the OP for his
website - to make the books into audio CDs.
(For the many people who are both, blind and deaf, there is braille. But you will need to be kinda dedicated to turn the books into braille, and to teach it to your parents.)