By college your kid needs to choose a favorite among diverse interests. Related majors also to consider. In college one cannot do it all, but must narrow the field. By now he knows if STEM or social sciences/humanities are more to his liking. He needs to sit down and make lists of reasons to choose majors. Courses needed and courses no time for with the majors.
For STEM majors he will need to start with the math and science sequences freshman first semester. Will those requirements interest him or will he chafe at not having time for more than one in the fields for different majors? He should look at his current classes- if he had to drop any which would he keep/drop? Priorities.
Many schools now want a declared major. Important to look at the ease of changing majors later. Easier within a school/college but majors often have limited enrollments. His stats may not get him into some schools. Unweighted gpa matters. A university may be a better choice for some majors than a LAC. It will help him to look at various schools’ requirements for majors of interest. Looking at those can he see himself being excited about the advanced classes?
Many end up with MBA’s with different undergrad majors. He should look at undergrad business majors, their requirements and limits on other courses due to time constraints. Does he want to limit himself as an undergrad to just business? He should look at job requirements and jobs for after his degree with the majors of interest. Can he see himself immersed in any of the fields?