Does he love NYU…?? NYU is a great school in many ways but it doesn’t have much of a cohesive community … and so I’m not sure exactly what it’s offering you. You say “prestige” but my understanding of entering med school is that the prestige of a school is less important than the GPA and MCAT tests.
Plus he’d be communiting–unclear how far the commute but the time involved could be serious.
Before deciding, check that I’m right by heading over to the premed threads and asking the very knowledgable folks there. They have charts and such that can help you figure out the GPA and MCAT combos etc.
Anecdotally, a friend with one child in Princeton and one at Harvard who both were premed she often wept through her children’s years at these prestigious schools. She kept saying that being at these schools made it harder for her kids to get into med school because grades were harder to get. Others I’ve known who went to Yale for premed were shocked to find that they couldn’t compete at the levels they needed to in freshmen chem class and at that point lost the med school dream. Again to be sure that I’m right about this, check the premed threads on this forum.
So … to my mind, I’d go with Stony Brook if he likes that school well enough or equally with NYU and save money and pull down the grades he needs.