U of Denver could be another to look at. The music school has a Jazz Studies program, and the city has a decent music scene (and good public transportation access from campus).
Definitely agree with UMiami, especially if his enviro science interests are marine-adjacent.
Loyola Chicago was suggested; there’s also DePaul, which has a Jazz Studies program in its music school. Both have a religious affiliation, but so does BC; I doubt either is too religious.
Richmond, VA, could be worth a look - it has an active music scene, lots of jazz clubs, and a jazz festival. There’s both Virginia Commonwealth (VCUArts has a jazz program), and U of Richmond, which has a strong music department; and there’s a cross-registration agreement between the two.
McGill in Montreal could also be worth considering.