IIRC, Duquesne has one of the oldest music therapy degree programs (maybe it’s their masters program) in the country. Pittsburgh is a great city, in my opinion. Not sure how easy to combine these two interests your student has.
Re: university of Hartford…I think academic admission is very likely. But admission to the OT program is a bit harder, and I thought was a masters level program…actually I thought it was a five year program. Not sure how easy that would be to combine with music as a second major.
IOW what I’m saying is make sure your son can actually in reality DO what he wants to do at each of these colleges. It’s not easy to double major with these two fields.