Broadening the question from "parents" to "family members", I treat it like any other request for help. If I owe them a favor, I'll do it no questions asked. Otherwise if I can help and I have time to help and it's not out of my way to help, I'll do it. I'm not going to drive 45 minutes out of my way to spend my Saturday helping my wife's second cousin with their printer unless I owe them a favor, but if they bring it to me at a family event I'm already attending I will give it a try.
This was true of my small business consulting days years ago. If the business (owner, management, workers) want the change and could ( in my opinion) maintain it then then I bid on it otherwise not.
Those companies I am still aware of that said "do it for me" have had multiple service provider because of burnout or boredom of the service provider. They were developers or configured specialty applications. They were not interested in doing the companies daily backups.
The ones that learned kept coming back for more projects that were helping them move forward and kept me interested.
I have managed to switch both my mother and my father over to macOS, which significantly cuts down the amount of time I need to spend on helping them out with their computers.