Hey, finz, I have heard of very FEW who pay even close to full tuition in a school like this (former guidance counselor here).
Forgive me if I am over-stepping boundaries -- OR mis-remembering (as I am VERY prone to do these days -- ARRRGGHHHHH) -- but, aren't YOU thinking about re-locating to a less expensive city once your child/children are out of the nest?
Nashville is a totally delightful city. No, I don't live there, now -- but, have lived there. One of the top hospitals in the nation is there -- Vanderbilt. And there are lots of cultural activities. Compared to many Northern cities, housing is CHEAP!
Just saying..........
BTW, if your income is within a certain amount, you might be able to get waivers on applications. (Used to be the case -- it has been awhile since I've been a GC, though.) You just need to make a call to the admissions counselors/offices at the schools your son is interested in. Telling them that YOU are on SSDI might also help.
I would also suggest that your son make a video showcasing his best abilities. Many schools with music programs have groups that represent the school (traveling/recruiting/doing concerts for the other students) -- and give great scholarships to the group members.