Social Sciences 4 years recommended?

Per UIUC admission requirements - 4 years of Social Sciences are recommended in high school. My son will be completing 3.5 years of social studies and planning to take 6 years of science courses(including ap bio, ap physics and ap chemistry) at the end of high school. We are concerned if uiuc truly prefers 4 years of social studies. Two questions

  1. Is consumer economics(Illinois state graduation reqt course) considered a social studies course?
  2. If 4 years of social studies is needed - should we ask student to take a semester social course in coming summer? He is sophomore now and already signed up for Govt and Consumer economics for coming summer. He is thinking to go to Japan on student exchange program next year summer. Is it too much to handle three semester courses in one summer.

Thank you for expert advise.