Now this is JMO so pls do not take any offense....It sounds to me like he does not even have ADHD. The issue seems to be with the treatment of him versus his siblings. I say that because you yourself mentioned 2 things. 1."He continues to tell me that I don't love him and I let his brother and sister do more, get more etc" and 2. "When I told him that his brother wasn't getting to go he said it would be the best week of his life".
Have you and your husband actually sat back and looked at the situation from his point of view? What could have made him make those statements? Kids are a good judge of character and they don't just act up just because. He's screaming your for attention and the only way he can get it is by acting up..He figures if I act bad, I'll get attention. (Which he does) Even if the attention is him getting in trouble, he's still getting it. Honestly I think what made him act up that day was you scolding him for saying it would be the best week of his life. Again, you are "sticking up for his brother and taking away his joy of having alone time with you.. I mean yes you were right to scold him but in what tone and context did you "talk to him about that comment"? What was his response? I feel for you and I can understand your frustration BUT I have to question again, what is it that makes him feel like you love his siblings more??? There's got to be something if you think long and hard..He was very specific in his choice of words so can you TRY and empathize with him and see where he's coming from?
If he's recently been taken off ADHD meds, it's likely he's pretty severely depressed. I had a son on a VERY low dose and the doc's warning was, don't take him off suddenly, it increases the risk of suicide.
These drugs really have such a profound affect on a person's mood. They have highs and lows while on the meds, and when suddenly taken off, can suffer debilitating depression.
Where is he in the birth order? Is it true what he is saying, that his brother and sister get more, do more?
Kind of think that mrspincince052519 missed the main point. You sent him off to summer camp without his brother and he was terrible. Actually, he did pretty much what many kids have done that I have read about over the last 4 years I have been responding to the ADHD forum. And, of course the most obvious point is that if the meds he is on are stimulants, and it makes him a zombie - ya, its probably ADHD. Any normal kid would be wired higher than a kite on stimulants. (he is on stimulants right, and not some other kind of a drug - that would change things).
You say you have adjusted his dose a dozen times. Have you ever changed his meds? There are many stimulants out there and they all effect the child differently. I think that leads to my next question. Are you doing this all through a pediatrician? I think that a pediatric psychiatrist by now would have tried several different meds, not just different doses.
You ask what you can do. Well, the fact that you are, "we are a strong Christian family and have a strong family foundation." Has got nothing to do with ADHD. Frankly ADHD doesn't care what you are. You need to learn all you can about it, so that you can help your child. He didn't wish for this. In fact, he probably inherited it from somebody in your family. You owe it to him to find out all you can about this.
On the ADHD forum where I normally post, the book I recommend the most is, "The ADD/ ADHD Answer book," by Susan Ashley. Buy it - it will help a lot.
Also, I should add. If you ever send him off to anything like the camp (and he is not on meds --or maybe even if he is) - you need to inform the counselors about his condition. The way you work with ADHD kids is different than with regular kids (book give good ideas here on discipline). I've worked with ADHD kids for years in a classroom setting, if you know and understand how to work with the child - wonderful things can happen. If you just think that he is a behavior problem - bad things happen.
I can give you a lot more resources if you are interested.
Oh, and ya - his brother and sister probably do get to do a lot more. That's because you can trust them. A real important part of helping an ADHD child is helping them to understand what is affecting them and how to deal with it. I guessing that you have not had a lot of profession help with that? Also, he should have a 504 for school. Has any one at school talked with you about that?