I don't think this diminishes your point, but, for a thing like memory, your father may be maintaining it by insisting on relying on it. It may diminish regardless, but its diminishment may slow down.

At work, we are in a certain kind of race. In life, we are in a certain other kind. To paraphrase a recent Brandon Sanderson talk about creativity in an era where AI can outpace and possibly soon, out-quality a professional, "The work you do on _you_ can be _the art_."

Strongly agree! As someone who has been caring for a parent with dementia, it's definitely a use or lose it kind of situation. See also the studies on long term cognitive health in London cab drivers

https://www.statnews.com/2024/12/16/alzheimers-disease-resea...