Also, make sure your son does a deep dive into the curricula for cognitive science when he is deciding where to apply. Some programs are more psychology-based, some more neuroscience-based, some more linguistics, and some more computational. He should make sure he is comfortable with what is offered/required and also if he has a strong interest in one sub-area, to make sure there is sufficient depth in that are for his time at college.
Most colleges publish both the requirements for the major as well as an online catalog of courses that are offered each semester. Note that sometimes a particular course may only be offered every other year.