I'm slowly compiling an Online Privacy Guide for my family and friends (I'll eventually make it public too). I am aiming for it to be very easy to read, understand and execute, think "could my mother ...
The canvas is a great metaphor for privacy, every pixel you place is a choice about what's visible. For your guide, I'd start with the basics: encrypted messaging (Signal), password managers (Bitwarden), and VPNs that don't log. Remember, the goal isn't perfection, it's giving your mother agency.