Pushing and Hooking

My 17 year old son has what looks like a great swing and tempo. He is very flexible and has wonderful pace. He also hits the ball a long way with a smooth swing. People have said he swings like Ernie Els, not a bad model to shoot for. His one problem which has been consistant for years is that he either pushes straight right or hooks, I beleive the 2 are related. He has seen pros and they normally suggest taking the club back on a straighter path. I believe that helps but just feel there are a few basics none of us are seeing.

Any ideas?

the two are related. basically coming into the ball from too inside a club path - so either the face is open at address or he is compensating by flipping his hands over causing the hook.

I agree but have not been able to find a drill that would help get the club on a more outside path. Know of anything?

After reading Hardy's book am reluctant to suggest anything as there are drills for both the one plane and the two plane swing. Having said that, you can get a swing plane on ebay for less than $40.00. There are several drills on the videos that deal with this problem.