My dad is in his 80s. He keeps careful notes on how to use devices like tablets and TVs. There might be a touch of engineer-brain at work here, but the struggle

My dad is in his 80s. He keeps careful notes on how to use devices like tablets and TVs. There might be a touch of engineer-brain at work here, but the struggle is very real. He generally wouldn't take in all of the text and symbols on a screen if there is a lot of going on, or might get hung up on the wrong parts of it. He generally wouldn't find a modern interface at all "intuitive". Any change to an interface is going to disrupt this, so one thing would be to change the interface only very rarely and carefully.