My brother loves playing something called cue sports but I don't know much about what that is. Is it like golf or pool?
It's basically a broad term for a variety of games of skill generally played with a cue stick, like billiards or pool for example.
Oh awesome. Is it a popular sport in the United States?
parts of the world. For example, in British and Australian English, "billiards" usually refers exclusively to the game of English billiards, while in American and Canadian English it is sometimes used to refer to a particular game or class of games, or to all cue games in general, depending upon dialect and context. In colloquial usage, the term "billiards" may be used colloquially to refer to pocket billiards games, such as pool, snooker, or Russian pyramid.
There are 3 major subdivisions of games
Cue sports
Cue sports (sometimes written cuesports), also known as billiard sports, 
are a wide variety of games of skill generally played with a cue stick, which is used to strike billiard balls and thereby cause them to move around a cloth-covered billiards table bounded by elastic bumpers known as .
Historically, the umbrella term was billiards. While that familiar name is still employed by some as a generic label for all such games, the word's usage has splintered into more exclusive competing meanings in various