Given this high school math, what is my son ready for in college?

Applied math folks have opportunities in companies that do numbers crunching AC Nielson, SAS and management and technology consulting firms,operational research many of them make it in to the technology realm… I would go for an Applied math degree from a top 10 school vs. a CS degree from an ‘also ran’ kind of institution. If you have looked in to the Courant School at NYU, it is a renowned one in the east coast along with Univ of Michigan in midwest. Check out the rankings here

http://grad-schools.usnews.rankingsandreviews.com/best-graduate-schools/top-science-schools/applied-mathematics-rankings