I wonder why the school says no to ABA??!! Did they give you a reason why?
There are alot of programs out there that help. They do vary from state to state.... what state do you live in? Some states have programs that pay for intensive services. Our son is HFA and will be starting intensive in-home therapy next month.
Your son sounds like how my son was at his age. I figured out that he was very sensitive to MY emotions, and when I was feeling frustrated and at my wits end (which was 90% of the time) he responded negativley. I made myself relax and talk slowly and calmly even when I wanted to scream! The more you do this, the more you will actually FEEL more relaxed and calm, and it was at this point that Jacob would relax. It is hard at first, but it is scary to kids (even non-autistic children) when they feel like the situation is out of control. It may be something to try....
There are alot of people on this board who have excellent advice and are here to support you. You are definitly not alone!