My boyfriend's neighbors hate their dog.

Ok so long story short there is an Asian family (I believe Chinese) living across the street from my boyfriend. The man is very traditional, cold hearted bastard that hates his life, wife, and dog. His wife is a young, bored, prescription drug addict that does anything she can to get her husband's attention. They both take their stresses out on their dog. The poor thing is constantly being left outside on the front porch at all times of the night/day and during any weather rain, hail, or blistering heat. He used to come over to our yard because he was lonely but once they realized this they started tying him to a tree. now he ust whines and runs in circles trying to break his leash. One day he's going to get caught and choke himself to death. I try to go over and comfort him whenever I can, and have had several conversations with the family trying to dissuade them from this behavior but there is a large language barrier. The police, paramedics and animal control have already been called to this house (mostly due to the wife's odd drug addled behavior). So, at last, my question is, should I steal this dog? Both my BF and I have homes with friendly dogs already and are more than capable of taking care of him and giving him a loving home. Just in the short time I've had to spend with him chained up to the tree I've been able to teach him to sit, lay down, shake, and roll over. He is a good dog. I just want to do the "right" thing. Edit: The other night it was around 35°F and the dog was tied up outside shaking and whimpering. I shit you not the wife comes outside, yells at the dog, then points and laughs at it and goes back inside. These motherfuckers need to be taken out.