Out of control 6 year old

My child has adhd and odd.he is so mean to our dogs , he hits them in their face. He says I hate him . Then when I say I don’t him he continues to argue . Then I just get quite to stop him from arguing . He does not listen to us. He lies. It’s like his reality is skewed. He blocks us out. Then other days he is an angel. I feel like we are dealing with a bipolar kid . My husband start off very calm with him but then some days when we are tired he starts pushing our buttons and we lose it . What seems to work is to not engage but then he starts nagging over and over .. it’s maddening . What can we do?