You are just stubbornly ignoring what you already know -- "Agree that major and minor doesn't matter for medical school application as long as prerequisites are completed," but "I am seeking guidance here from experts about this new track to make an educated decision and how it may or may not help his pre-med journey."
How many times, and how many different ways, do you need anyone who knows what they are talking about to tell you that med schools absolutely do not give a crap what your kid majors in, they only care how he does? Do you really expect anyone on SDN to know how your particular kid is going to do in Computation and Systems Modelling as compared to Human Behavior and Cognition?
So, keep being a helicopter parent, and keep being frustrated because the answer you don't want to hear is to leave your kid alone and let him do what he wants, because that is most likely, with no guarantees, to yield the most success. You are not going to receive a definitive answer here one way or the other, for you to throw back at him as you "guide" him on what he has to do based on the collective wisdom of a bunch of random internet strangers he couldn't care less about!!!!
Why not just put all your hard work to good use and apply to med school yourself???? Then, at least you can lead by example!