Hi, I strongly recommend that you read Russell Barkley’s books. One is specifically about managing the behavior of adhd children. The Kazdin Method for Defiant Children is another book by a different author that I can recommend. Both barker and Kazdin have a similar philosophy about managing behavior.
I would also recommend working with a professional therapist whose specialty is adhd. Look on Russell barkers website. Russell barker is the expert on adhd and has a clinic. Maybe you could even visit his clinic, do a phone consultation with him, or ask them for a recommendation for a therapist in your area.
Is your son doing any activities outside the home that could give him a positive focus? Sports? Hiking? art? I would try really hard to involve him in something that will make him feel good, even if that means taking him out yourself into nature for some hiking for example. I would also
If you read the books I mentioned above, you will see that lecturing, arguing, reasoning and criticizing is the wrong approach. Instead, the rules should be made clear and when the rules are broken, a consequence is given. Do not engage in a discussion or argument. If he harasses you about it, continue doing whatever it is youre doing and ignore him or leave the room. If he follows you and continues and you can’t take it anymore, calmly step outside for a few moments. (Don’t be dramatic about it. Just say something about needing to get something out of the car or whatever) Afterwards, don’t hold a grudge, or at least don’t show that your upset. Just move on. When you start implementing these strategies, he will increase his efforts to argue and get a reaction out of you but stick to to the program. It may take a while but after a a while he will start to see that the old behaviors won’t work anymore.
You do need professional help and guidance though. You’re in a difficult situation and you need support. But I can’t stress enough that you need to find a professional who is highly experienced with this population of children! Don’t just go to a regular therapist who claims to have SOME experience with defiant adhd children.