When I was a kid in the 1970s, I took a couple of years of violin lessons and played in school to please my grandfather, who I loved, and wasn’t pushy about it. He had learned to play at age 4, helped found the Tucson Civic Orchestra (he was concertmaster for a time), and played until his 80s, when his arthritis made it impossible. As the owner of furniture stores, his inner life was music, all the time.
May I recommend
Norman Monath's "How to Play Popular Piano in 10 Easy Lessons: The Fastest, Easiest Way to Learn to Play from Sheet Music or by Ear"?
My father told me, for the piano capability I wanted (high-yield learning, low expectations beyond a wee sing song), learning to read a fake book would be the optimal path. He was right, and subsequently a fee of my friends have learnt from the same book! There are usually some cheap copies on AbeBooks.com