@juniormom2 If he’s applying for CS I’d argue that it’s an ESPECIALLY IMPORTANT COURSE: colleges will want evidence that he’s actually explored the area during high school. Knowing CS is never a bad skill to have as well. However, as @skieurope says, taking the core courses should be your son’s primary concern throughout high school, and challenging himself in advanced classes in his fields of interest.
I go to Brown and their bulletin has a helpful list of courses they recommend students to have: https://bulletin.brown.edu/the-college/
"Subject Requirements
Brown’s commitment to fostering a liberal education assumes that a candidate for admission will profit most from pursuing a comprehensive college preparatory program. A strong background in English (both literature and writing), foreign languages, mathematics, science, and history will enable students to benefit from the intellectual opportunities offered by Brown University. Brown considers the programs listed below to be a desirable secondary school preparation.
English—four years with significant emphasis on writing, continued through the senior year;
Mathematics —at least three years of college preparatory mathematics, preferably continued through the senior year;
Foreign Language—at least three years, preferably continued through the senior year;
Laboratory Science—at least two years of laboratory science above the freshman-year level. Prospective science or engineering students should take both physics and chemistry, and as advanced a level of mathematics as possible;
History—at least two years, including American History;
The Arts—at least one year of study in music or art;
Elective Subjects—at least one year of elective academic subjects;
Information Technology—facility with computers is recommended for all applicants.
THIS IS IMPORTANT!! ADMISSIONS CARES MORE ABOUT YOU CHALLENGING YOURSELF IN STEM IF YOU ARE APPLYING FOR STEM VS. IN ENGLISH and vice-versa.
Exceptions may be made. The Board of Admission encourages the growth of innovative programs and welcomes applications from students of varying educational backgrounds who have shown outstanding intellectual promise. Exceptionally able students who are well-prepared to enter college before completion of secondary school may also be admitted, although such cases are unusual."
Hope that helps!