That's some pretty harsh attitude he has toward you Crudemood, almost like you're the "big disappointment". And that doesn't necessarily mean you are, but obviously he has such a clear picture in his head of what your life should be, he won't even let you figure it out yourself.

I think you should say to him that the only way you're going to learn how to run a life, is to be allowed to make your mistakes and learn from them. Nobody becomes a successful and independant person by having somebody else order them since they have it "all figured out".
And tell him, strait out, that he constantly belittles you and won't let you have an opinion. Point out that it doesn't even matter if you're "right", if you want to buy a guitar or take karate or become an artist, whatever, it's your right to explore that avenue and find out for yourself what comes of it.
Or heck, just show him this post if you don't want to speak up, or can't.