Do you know anything about the teachers available for the next school year?

I would likely not send an e-mail, unless it is just simply to set up a time to discuss next school year. I am finding these initial questions are best discussed either in person or over the phone, where you can better explain things and more importantly, read verbal tone and body language.

My approach would likely be to simply say that DS struggled with not wanting to go to school this past year and some of the things he has said. Then ask, do you have any suggestions for how we can make next school year more palatable for him?