When we see a dog that has been abused it is so easy to feel sorry and shower the dog with affection.
Unfortunately, in doing so we can easily overcompensate and end up with a dog full of entitlement who has no idea how to respect boundary.
In other words, we can end up with a spoiled brat.
A dog like that is not in a happy place. He is confused because he does not know the rules of our world; he is lost because he has no guidance and no one to look up to for direction; he is anxious because he cannot control his impulse so he is always in a go go go mindset; he is stressed because without your leadership he feels vulnerable and insecure.
Show your dog what you want from him by installing a clear structure in his life, introduce the dog to our human world by explaining our rules to him via reward and correction, teach him our language via training and life inclusion and lastly, please show him respect by treating him as a dog--not a stuffed animal...
Be gentle yet strong, be kind but firm, and be loving and respectful.
Forget about his past and stop feeling sorry for him. Self pity has no place in leadership.
Honor your dog by preparing him for his new life the way you would with a "normal" dog so he can reach his full potential and live a fulfilled and enriched life.