He could do marine bio and still check all the boxes for prevet. UNH or UMaine are both well positioned for that with top marine bio programs.
Have him go to the admitted student day at UNH with COLSA. It helps them to hear other kids from further away be really excited about what they offer. The Isle of Shoals program is with Cornell and very well respected. He could knock out some summer classes there any make an exchange semester or year even easier. Money saved allows for other things potentially and flexibility with internships, etc…