"Ok Grandma so you can't look at a picture. Here is what you need to do - drop to a command line and start your ssh server. Check to make sure that the port is forwarded so I can connect on my end with VNC. Ok that all set up? Great now I can start to help you."
An operating system is not a panacea. What I have done with my family, instead of ramming something down their throat that is likely above their abilities, is to teach them good basic security practices, and that bad things can happen if you are not careful no matter what software/OS you are using. I taught them to be security minded instead of giving them the illusion nothing bad could ever possibly happen because I am using {Product X}. Guess who gets a lot less calls now? And how are you going to make them use Linux on their iPads, or do you also get to dictate which technology products anyone in your family can buy as well as dictate which software they can run?