On organizational issues, I've also seen that teachers see the need to remind all the kids during the first part of the year, assuming they can pull back on that later and have it stick. So not only are they forgetting about his IEP accommodations, but they've also removed some of the support that it otherwise just there. We've struggled with this part repeatedly.

Is this middle school, so these emails are coming from multiple teachers?

If so, it might be useful to make each teacher aware of what the others are seeing. Is there a school councilor that meets with the teachers and keeps tabs on the kids? I wonder if he's seeing it coming from all sides, while the teachers are only seeing their little slice of him. A little criticism from each teacher seems innocuous to them, but compounds to a death from a 1000 cuts.