Boy,lots going on here. The first thing that comes to mind is it really PANDAS? Because, that does effect how this is handled. "The hallmark trait for PANDAS is sudden acute and debilitating onset of intense anxiety and mood lability accompanied by Obsessive Compulsive-like issues and/or Tics in association with a streptococcal-A (GABHS) infection that has occurred immediately prior to the symptoms. In some instances, the onset will be 4 to 6 months after a strep infection because the antibiotics did not fully eradicate the bacteria." "PANDAS children may have moderate to dramatic improvement with antibiotics within one week of treatment, however, further interventions may be needed. How to stop the entire syndrome is still debated, but many parents and doctors report prolonged antibiotics (two months to one year) and/or IVIG (intravenous immunoglobulin) treatment or plasmapheresis." The term "sudden acute" seems to be important. So did this suddenly happen?
And even if it is not PANDAS, because he was treated with antibiotics, his gut bacteria is messed up and that can effect him in a variety of ways. I would definitely try some Probiotics. Don't go too crazy at the start.
In terms of meds, you said, "All stimulants made him hyper and agitated." The reason I mention this is because if Prozac is given with a stem medication - this effect can happen. Basically Prozac blocks the liver pathway for the stim medication. The medication then can back up, concentrate, and give symptoms like you mentioned. This link explains it in detail - http://www.corepsych.com/2006/11/adderall-prozac-and-paxil-problem-not-solution/
If your son was taking Prozac at the same time as the stim meds, that might be the reason for the problems.
I am surprised I did not see an ADHD diagnosis mentioned.. He certainly has the symptoms and the other things you mentioned are all fairly common co-disorders. The fact you said the stim meds were tried, does lead one to assume that at least at one point in time - that was the thinking. What changed?
Now the interesting point is that the school says he is great! Would I be correct in thinking that school was more of a challenge before the meds started? It does sound like the meds are working. However things fall apart at home. One reason for this is the length of duration of the meds.
Tenex can be an effective med for ADHD (not as good as stim meds, but still good). However, Intuniv (a newer medication like Tenex), "is once a day in AM, longest duration, least sedating, often smoother and is a new brand." Might be worth trying to see if it extends into his home hours.
It really does sound like you are really trying to help him. Many, many parents who I have helped on this site -
http://www.medhelp.org/forums/ADD---ADHD/show/175 - where I am also the CL have not bothered to do the social groups and the psychologist. You have. Because of my work on the above mentioned site I have found lots of very helpful parenting links. This is a good example - http://www.additudemag.com/topic/parenting-adhd-children/behavior-discipline.html
So essentially, I have a ton of information on helping kids with ADHD. What you have is a child with a bunch of diagnosis that may or may not be completely accurate. This is a good link on OCD and ADHD - http://www.additudemag.com/adhd/article/6113-3.html - which might be helpful.
So talk with your doctor about Intuniv. Take a look at the link on "parenting-adhd-children/behavior-discipline" it will help you at home even if he does not have ADHD.
Please let me know if there are any more types of info you need. I hope this helps a bit. Best wishes.