It hurts me as well to hear you say your dad hits your dog. I know how it goes. "Oh I want a puppy so bad I will play with him every day." So your parents give in but the dog has to stay out side. For a while you play every day. Then one day its raining or whatever so you don't go out that...
They probably have a bit of your and your boy friends scent on them. They remind him of you and make him feel comfortable.
Try giving him a old sweater or clothing that you wore and I bet he will like that even more.