Thanks for your thoughts snowgirl. Yes, my son is also a strong visual spatial learner (with auditory sequential weaknesses). He is also strong at expressing himself verbally (but not singing :)). It is interesting how you have mentioned that the musical perception is different when it is not coming from within yourself. I think I will try him on an instrument as you suggest - my brother is in a band and plays guitar so perhaps I might ask him.
Tiz