"With your body moving as it is and the way your arm is following, you are essentially generating outswing through your action and not through the tools that Dale Steyn uses. If you can get yourself upright and aligned, those may be much more use."
Tim, this is very true and you have given some great advice here. His action is really geared towards bowling out swing which is not a bad thing at all. The only problem is that he will not be extracting maximum bounce from the wicket, bowling the straight one or even I swinger will be very difficult and he will be swinging the ball out of the hand and not getting later swing.
As a seam bowler yourself, what would you advize he do to adjust his action without changing it too dramatically? Getting a bit mre upright at delivery and possible opening up a bit with that front leg?