Unless you expect to qualify for a lot of need-based aid, I’d go where the cost is the least, meaning flagship state U. Med school is very expensive. You want to keep the cost low. They’re gonna look at his GPA overall (so he should major in whatever he loves, and not necessarily science), and at his grades in his premed courses. And high MCATs. Then they’ll also look at whatever he may have done to demonstrate interest in medicine, be it research, volunteering, whatever. Sure, if you’re coming from an Ivy, or Ivy equivalent, they’ll like that, but is it worth the price?
Also, if it were at all possible, I would seriously consider student’s becoming in-state resident in one of the states where med schools are many, and cheap. I think the best deal is Texas. That means license, voting, part time job, taxes, paying a utility bill, and eventually filing own tax return, not as your dependent (depending upon how it affects financial aid).