I have met with many parents who thought that nothing could be done to improve the relationship. But it is possible, you just have to work on it. They're stuck in their own idea of solving things, but sometimes we need a third party to see things from a different and objective angle. When you see behaviour changes, you'll be able to open up and see the opportunities right in front of you.
Behaviour is always coming from somewhere. You need to be a sort of detective to figure out what the problem is and how to react on it. I see a lot of children with anxiety for example, but they show this in a repetitive way. They sometimes like to crawl back in their shell or display "naughty" behaviour. It is just a cry for help: "please I can't cope", "I'm scared" or "nobody understands me". It can also be: "help give me boundaries because I have too many options to choose from". So if we can find out where the behaviour is coming from, we can often solve the problem.