Dog will walk nicely on leash with me but pulls with the owner, driving him mad

Without more info I can't really give you a detailed response but it sounds like the owner of the dog is not the alpha in the pack.
It sounds like the dog treats YOU as the Alpha, and his owner as his pack-mate.
Dogs work in hierarchys, they have a distinct leader and everyone else in the pack follows.

To establish yourself as the leader of the pack you have to give your dog tasks and rules.

Obedience training is a great way to help start this off. You can sign up for classes at local dog clubs or just learn from home.

Can you tell me what the owner of the dog does during walks...
How do they try to correct the bad behavior?