What a beautiful, sweet answer. Of course he is probably just being a normal, 17 year old, pulling away from his parents and asserting his independence, but to treat him with such compassion and respect could go a long way in asssiting him in grow up to be compassionate and respectful of others himself.
I like the idea of music with subliminal messages at meal time. (Or any time he is home for that matter.)
You might also want to try some Bach Flower remedies for anger, if he was willing to take them.
If there are any other symptoms, however, such as his grades dropping, his hanging out with new, unsavory friends or skipping classes...you might want to make sure he is not abusing himself with drugs