If he wants to go to graduate school, grades matter as a necessary but not sufficient condition. However, if he's a promising student, he'll have no problem get

If he wants to go to graduate school, grades matter as a necessary but not sufficient condition. However, if he's a promising student, he'll have no problem getting the requisite grades (3.5+ in-major) while working on independent projects and doing research. He might also decide he wants to go to law or business school, in which case undergraduate GPA is a significant selection criterion.