Being the father, and being "Asian" where parental control pervades throughout the children's lives, I wanted to put my foot down on the whole matter and have my son take a second "backup" course aside from the piano .... here in Manila and not in the US.
But how does a father steer his son away from his happiness and joy? How does a father guarantee to his son that his plan for his son's life is the superior plan? How does a father live with the fact that he may be suppressing a gift for the arts and music that his son may possess? ETc...etc..etc...
Maybe a weak side of our culture is being fatalistic. We as parents have decided to support our son's wish to someday become an accomplished pianist and we leave the rest to GOD! Is that a good thing .... logically NO!!! 
MY is it difficult to be a parent!!! 
My parents discouraged it and I was upset. But I did a regular liberal arts schooling, continued to study piano there, graduated, worked as a journalist and realized I couldn't let go of music. So, I decided a good compromise would be to write about music, criticism and reviewing. So, I went back to school and quickly got a masters in piano performance and guess what I realized after doing all those recitals, master classes, lecture recitals, etc? I realized that it would be intolerable -- knowing how difficult it is to play the piano beautifully -- to devote my life criticizing my betters.
So, back to square one. Then it hit me: my folks always wanted me to have a profession for safety. So, I became what I am now: a psychoanalyst. I specialize in performance anxiety and work with musicians and actors. I hear their complaints and also their great joys at being performers. No performance life is "easy." I admire them for their choice and sacrifices. But, you know what, I don't envy them. Music is my mistress not my wife. It's an easier life for me.
I think you can only be a pianist, an actor, a painter, a writer if doing without it would be the ruination of your life. Almost like a drug. You MUST have it. I'm not that sure, however, that life has so few options, so I expanded mine. I'm quite happy with my choices and would not do them over.
What would I say to my son or daughter who wanted a music career? I'd explain the realities of it, warn them against it in this miserable economic climate, but I ultimately would let them make the choice. If it's the wrong choice, it's fixable and there are other avenues to success and gratification in a career. Many people find their true callings in their mid to late 30s after trial and error. With that experience comes maturity and the correct career decision.
Don't worry, Dad! Let him go. He'll find his own way, particularly if you've been loving and supportive. And it certainly sounds like you have been.
Topic: This is the LAST THREAD I'll make about college applications