I think a lot of people think the Greeks run the show at the big schools, but that’s just because they are doing things as a group - making homecoming floats, wearing the same sweatshirts to the football games, posting about events and parties. But really the majority of students are not in Greek life at the big schools. 20% would be a big number in Greek life. At some schools there are enormous houses on campus, but at most schools there are not (sororities more than fraternity houses). Often the Greek houses are off in an area of campus away from the main drag or the dorms.
I don’t think he’d notice the Greeks if he decides not to rush and to find other activities.