It used to be you could find a box of photos or keepsakes that you inherited to look back on how things were or when you were a kid. Now, most of that is stored on phones, and most parents probably don’t think to share or save them in a way to be passed down in the future.
My mom has SD cards with thousands of photos she takes as part of her job and it drives me nuts that I have to keep telling her to back them up. She always says that she’s never had one fail, which is true, but she’ll unfortunately have to learn this lesson the hard way at some point.
Setup something for her that’s easy to use. An adapter that once connected simply copies everything from the card to a specific folder.
Make sure the computer that this is on is also backed using something like backblaze or crash plan.
Remember small steps. Start with copying the SD cards.
Then work on computer backup.
Then later add a tool(s) for managing the images, there’s some good stuff out there.