If he is feeling angry and frustrated, it could be vitamin d deficiency. When my family starts getting that way, I push some vitamin D, mostly via sunshine, that is the most effective.

Frustration with the teacher is the problem. Using supplements for one problem area?

I am not sure if you have tried or implemented the 5 point scale, but it maybe beneficial for your son. The 5 point scale shows images of how an individual is feeling and what are appropriate responses to tackling those challenges. To ensure the best strategies/supplements are suggested for son, may I ask what type of learner is your son, which modalities (visual, auditory, kinesthetic...) does he appear to align with more than others?

Wow.. that must be one ugly teacher

It seems to be with the teacher .