Your dog thinks he is the Master so your behaviourist will show you how to change that!! Its a pity that you didn’t organise this before, but since its done now, the dog can only improve, once you keep it up. When your boyfriend sees whats happening, he will change his mind, but he wont do that until he feels that something is being doing to help the dog.
Good luck with the training and be consistent with it. The rewards are wonderful!!