I agree that it could very well be anxiety. Even if you and your dh were perfectly calm and in control over the last few years, kids are attuned to the stress that's going on in your lives and y'all have had a lot. My DD sounds a lot like yours. She was miserable all the time and seemed to argue just for the sake of arguing. Meltdowns over every little thong and the inability to get herself under any sort of control finally prompted us to take her to a psychiatrist. She was diagnosed with anxiety originally and ADHD more recently. The doc said impulse control (the lashing out, angry responses) were classic ADHD in girls. I originally fought the idea - we tried diet modification, cognitive behavioral therapy, I read every book in the world on strong willed children - nothing seemed to help. When we started Zoloft for the anxiety it was like I finally had my sweet DD back. She's a funny, quirky, goofy girl when she isn't miserable. I was really concerned that she'd lose some of that on meds. Really concerned. Instead she is more confident, more willing to listen to reason, better able to see the good in things.
All of that to say, I'd have him evaluated. Dh was/is a punitive parent too, but he's learned that if you give DD the chance to explain her reasoning for whatever, she's much more likely to listen to your reasoning. They still butt heads, but it isn't as much a control issue anymore. CBT gave her skills to deal with life and the Zoloft let her calm down enough to apply those lessons.