Berklee is a freestanding school of music, with a BM program. It seems you are looking for a school of music that is not freestanding but is, instead, part of a larger university where academics are also a focus.
A couple of comments: first, Berklee is part of a consortium, so classes can be taken at other schools, such as Northeastern. I have no idea how much this is used. It also has a new double degree program with Harvard, And of course it recently merged with Boston Conservatory.
Second, if you are looking at schools of music for this major, that are part of a larger campus, and for a BM degree, the program will be very similar to Berklee’s in terms of curriculum requirements. The difference is that Berklee is freestanding but the program will be similar.
It IS possible to do the intensive, immersive BM and do a double major or a minor in another subject, at some schools. But consider that a BM is 2/3-2/4 music classes, with lessons, practice, rehearsals and performance. Then add gen eds. Then see how much room is left for another subject.
Here is the requirements list, including gen eds, for USC’s BM. (They also offer a minor in popular music and minor in songwriting).http://catalogue.usc.edu/preview_program.php?catoid=7&poid=6849&returnto=1603
So if your son doesn’t want to study “just music” he might want to read the Double Degree Dilemma essay nearer the top of this forum, which details different ways to study music. He could consider universities or liberal arts colleges that have music departments that offer lessons, courses in his area of interest, and extracurricular performance, where he could major in something else, double major, major/minor or do a double degree.
If he doesn’t want to do “just music” for practical concerns or the need for a “backup” many of us on here will express encouragement for him to do what he loves in the undergrad years. Music majors get a bachelor’s like any other grad and can go to grad school or professional schools like med, law, business, nursing after graduation.
Then again, if he has an area of strong interest outside of music, there are ways to pursue that intensively but still continue music outside of the classroom or with limited classes in music.
Good luck!