I want to show an alternative approach to managing your documents:
Store them in your IMAP/Mails. Either on an own account or in a dedicated sub-folder.
I wrote some small python scripts [1] which allow you to: - Add an email with the PDF attached to your document collection. The script supports adding a subject and adding tags to it - Go over all the emails and run an OCR (tesseract) on them: Attach the OCR result together with the pdf to the email.
Big advantage: - Search on IMAP is a solved problem - Clients for every operating system in the world, including web, mobile - Super simple backup and restore
Over course, very geeky, nothing for your parents, but maybe something for you?