By 12-1-1 I assume you mean 12 students, 1 teacher, 1 aide but due to lower enrollment there are really only 5 students - right? But are these all spec Ed students? Is this a spec Ed teacher? Or is this just overflow students with a regular teacher waiting for an opening in a regular classroom? "Accommodating" the neuropsych's recommendations doesn't necessarily mean meeting DS's needs. The real question is are they looking to satisfy the letter of the law or to actually educate your DS? Do they want to keep the ex satisfied or do they want to do what DS needs? They don't like being in the middle of an obviously litigious situation and want to keep dad happy since he pays the bills. You have to be careful here but it can be done.
I think the thing that bothers me most with what you have described is the idea that this school may be playing at providing spec Ed services for your DS but is not being required to do it in a way that is measurable. Does he actually have an IEP? Last summer when you posted I thought you said he has one through your district and the district is paying the tuition (although you might mean they are paying for the spec Ed services he receives from the school - I'm not really clear on that.) In an IEP Goals and a Objectives have to be written in a way that the students progress is monitored and measured and you can see if he is making progress. You have said a couple of times that he hasn't made progress in 4 years, that the school "doesn't have a crystal ball" to determine when he will close the gap, etc. This needs to get addressed. This is concrete.
If I were you I would do at least one of these 3 things - maybe all.
1. Bring your son's IEP to your distict's spec Ed coordinator (or whoever oversees payment for the services he is receiving at this school). Work with them to make sure the Goals and Objectives are properly written and can be measurable, ie DS will properly decode irregular multi syllable words without context clues 8 out of 10 times or whatever. That they identify the skill, say how the skill will be measured, by whom and what the criteria will be for mastery. The district needs to ensure that he is actually receiving the services for which they are paying. Maybe the district can get the answers regarding qualifications of the teachers. Follow the money - district is paying so they have a vested interest even though your ex isn't holding them to FAPE. School wants to be paid so will likely answer to district even if they won't give you specific answers.
2. Consult with a dyslexia intervention specialist. In my area there is a private OG clinic. KJP brought her DS to a Lindamood Bell program. You will have to see what's in your area. These places will not be cheap but should be effective. Show them your son's IEP and explain he has made no progress. Let them explain how their program differs from what he has been getting, why they think they're program has a better chance of success, what he needs that he is not getting, etc. They may be able to draft better goals and objectives. You may even be able to get the district to cover some or all of this cost if you can make a good argument that what they have been paying for hasn't been effective and the school is unwilling or unable to provide what he actually needs. Or you (or the ex) may have to pay for this service out of pocket...
3. Find an advocate or education consultant who specializes in redrafting IEP's. When I first started on my journey I attended a multiple day training through a nonprofit that advocated for the needs of people with learning disabilities. It was a crash course in a lot of things I didn't yet need but over the years has proved *very* useful. There I met an advocate whose specialty was dissecting IEP's and forcing district's to redraft Goals and Objectives. She would take a single goal amd break it into 7 parts each with its own clearly measurable criteria. These tiny bite size pieces made it very easy to measure a students progress and ensured that everyone was looking at the same data the same way. Again not cheap but better than the educational attorney you mentioned in an earlier post.
I'm guessing the GAL said you were "over the top" because those really are not "worst case scenarios". It's easy to get sucked into the emotions of a situation when advocating for your kids. Try to focus instead on logical, practical solutions. If your DS11 is retained it will make it quite easy to argue the school isn't meeting his needs - right? But it shouldn't get to that point. You need to have clear, measurable progress reports a minimum of every 3 months. If he isn't making progress the program isn't working and needs to be tweeked. Calm, logical, practical. Clearly defined, measurable goals and objectives. Lather, rinse, repeat.
If you haven't yet review the info at Wrightslaw and get copies of some of their books. Even if your ex has removed the kids from the public school there is still good information there that can help you formulate a plan.