What is it grandpa is capable of doing, if not plugging the kindle in the computer and dragging and dropping a file onto the "kindle" device that is now mounted in his file explorer?

"OK, I opened the explorer, but I don't see it."

"Type 'kindle' in the search."

"Alright, hold on... do I want kindle.com? I'm on Amazon, now where do I go?"

A slightly more experienced fastball realizes grandpa has opened his never-updated Internet Explorer on his old Windows box.

Maybe your family is tech-savvy, but there's many who aren't.

If grandpa understands how to use email, he can also just email his kindle an ebook and it will appear on his kindle.