I second the suggestion to post on the music forum. The advice you will get there is a bit different from what you are getting here.
Here is a good essay to read about ways to study music: http://www.peabody.jhu.edu/conservatory/admissions/tips/doubledegree.html
I hope that if your son wants to pursue a performance degree, you will come to see that that may be fine for his future and not entirely dependent on an orchestra job.
Many musicians do sacrifice some academics in favor of practice, rehearsing, performing, and classes at, for instance, conservatory prep on Saturdays, and it can work out. For conservatories not affiliated with a university (free standing), the main thing will be the audition. For conservatories/music schools that are part of a university, usually he would have to get into both the university and the conservatory, with the audition being important for the latter. For a university/college program (BA) there may or may not be an audition for admission, but a supplement to the common application can really help with admissions: including a video or CD, a music resume, and teacher recommendations.
A BM or BA in music is as valuable as any other bachelor’s degree, and gives access to many jobs in music and outside of music, and access to grad schools, law or med school, etc. Often music students will do internships, work in outreach or education, gain skills in technology or recording, during their years of study that can also help. Entrepreneurial studies are big at conservatories these days.
Music education is a fine degree if teaching is someone’s primary goal, but I would not do it as a backup plan. I know it takes courage in this day and age but for undergrad years it really is okay to follow a “passion.” Music ed can be a grad degree (and so can performance!). Lots of possibilities after graduation.
There are many things going on in music these days besides symphony orchestras. You might want to buy a book online on the topic of planning a career in music. I wanted to give you a title but I cannot find it at the moment!
Another great book is “Creative Colleges” which covers music, art, theater and writing programs.
People on the music forum can give you ideas on specific schools but this post didn’t seem to be about that so much as the general idea of majoring in performance and the economic risks of doing that. There is a thread about this at the top of the music forum that you might want to read. Good luck!