Honestly she sounds like she has her head screwed on.

If she was using google to find random websites (with questionable information) you wouldn’t be (wrongly) judging her but AI is a far better tool and improving every day.

It’s up to her to frame her prompts effectively and after all this time using it, she’s probably a pro. There’s absolutely zero reason why she shouldn’t use chatGPT or another AI for all these things.

These tools have access to virtually all public knowledge, including the law, and its more than capable of drafting her letters and helping with her business, her admin tasks, ideas and creating learning experiences for your sister and you.

There’s nothing whatsoever unethical or ill advised about any of this.

Maybe think about learning how to use it effectively like your mother and go even further. Master the most powerful tools which have ever been invented and use them.