Wow EmmaL I feel for you - that does complicate things. I would still probably start with the public school district. Get an IEP drafted that shows the level of service they would provide if he were in public school. How do you know they would agree to out of district placement at one of these other schools? That could be powerful if it can be documented.
Once you have the input from the district I would meet with the religious private. Swallow hard and don't expect them to roll out the red carpet for you but meet with them and hear what they have to say. (My understanding is that while he may have "final say" for education you are not excluded from the discussion, just as he would be free to speak with doctors even though you have final say on medical issues.) Show them the reports and the new IEP. Explain that your ex seemed to misinterpret the prior report to mean "lazy" and "underachieving" rather than "disabled". Hear them out on their interpretation. How do they justify a 6th grader in their school reading at a 3rd grade level. My guess is they will jump at the idea of dyslexia over ineffective teaching but YMMV. Ask them what level of service they "can" provide and what level of service they "will" provide. If they can't provide the level of service the public puts into his IEP be sure to understand why. Is it something out of their control or do they disagree with the need or has no one ever asked before. If you can get the school to understand you may have a powerful partner in getting the ex on board enough to get proper services for your DS.
If needed have a meeting with the school and the evaluator and your ex afterwards so all are on the same page. The evaluator should hopefully be skilled at explaining the situation to your ex. S/he can also explain to the school or combine with the school to explain to your ex. It may be that the school will be responsive and find a way to meet your DS's needs. Or it may be that you get a whole lot of documentation to bring back with you to the family court. Assuming your concerns were confirmed with this last round of testing and you had to fight in court to get it done you will likely have credibility on your side if you ask for the court to intervene based on this new info.
Good luck. And please keep us posted on your progress!
