I agree-- this isn't about resilience.
It's about learning to deal with difficult people, all right. But think very carefully about the message that you're sending here, before deciding that this is something that you want your child to become stoic about.
When a person is toxic, (in general or just to us personally), is the answer "find a way to tolerate this situation"? Or is it "find a way to make this stop"? Or is it "know your own inner self well enough to recognize your limits as a human being-- and call a halt before it gets to 'damaging' in a major way"?
I'd argue that what most parents would LIKE for their child is the latter. Teaching them the first of those options in a setting where the toxic person has power over them is really teaching them to tolerate abuse, at least potentially.
I'm not suggesting that this teacher is being abusive-- just that stripping a child of his/her ability to express authentic feelings of distress is probably not a good way to handle it from a long-term perspective.
Learning to deal with difficult people also means learning when to walk away. That is a valid option, ultimately, between adults. We may not like the consequences of walking away, occasionally, but it is an option. The only setting which is comparable for an adult is... well, incarceration.
This isn't a situation that allows any empowerment for your child-- so it isn't really one that allows for the lesson of "choosing" or "learning" a variety of coping strategies for actively/assertively altering the nature of the interpersonal dynamic between himself and the teacher, per se. More like developing a tolerance for conduct that he essentially finds intolerable.
What if this were a peer? Think about the difference in strategic coaching you'd be offering there-- and WHY that isn't an option in dealing with the teacher instead. Consider the dynamic in light of the power imbalance that is inherent in the situation.
