I think you already agree with the last post about changing schools
I don't think this school gels with your values at all, apart from the umbrella interest in teaching in an Islamic environment.
I also think your DS would get a far more impartial view of the world even in a Catholic school, where I found going to school with kids from other religious backgrounds to be of great benefit to both parties (ETA: should probably mention that I wasn't Catholic, either!).
The most impartial view of the world you will get is in a public school, all religious schools have some kind of link (and I have taught in catholic and anglican schools as well as public schools). The curriculum is the same no matter what kind of school you attend.