I wish you the best of luck. I agree that your boyfriend doing the puppy classes should help. Heelers are definately a one person dog though. Maybe your boyfriend gets frustrated when the puppy won't listen to him and it shows in his voice? Or sometimes trying too hard for too much time is a turn-off for some dogs. If after a few tries, the puppy won't walk further with him, he should say "ok" and give up for a few minutes and do something else to put a break in the tense situation. When the puppy stops on the sidewalk he could sit down facing away from the puppy and see if the puppy decides to come to him. Then without paying attention to the puppy, get up and start to walk again and see if he follows. Just a few things to try.