Young family member is interested in physics, which books should they read?

If you ask the internet, it's full of affiliate links ( no surprise) but having searched to refresh my memory, the recommendations at live science look very reasonable.

https://www.livescience.com/best-physics-books

Of course, they list the Feynman lectures on physics, which are a classic, and which are freely available from Caltech.

https://www.feynmanlectures.caltech.edu/

Learn from a master!

The Flying Circus Of Physics https://en.m.wikipedia.org/wiki/The_Flying_Circus_of_Physics (the 'with answers' version) is a very entertaining gallery of unexpected physics effects, all explained without using math.

"Surely You're Joking, Mr. Feynman!" by Richard Feynman.

How to, what if? 1+2 and thing explainer all by Randall munroe. The latter one is the only one i can recommend for younger kids, it has only 1000 different words.

fun demos and lecture style for younger viewers, scratching open a number of fundamental topics. w. the professor J.S. Miller

https://yt.artemislena.eu/search?q=JULIUS+SUMNER+MILLER [videoz]

Depending on age, some Hawking would be good