And I found it disrespectful.

The kid has a habit of responding dismissively: "Ok", "Thank you", "Ok", and she flipped out, raising her voice, threatening to take away his phone for several weeks if he wouldn't stop badmouthing her.

We were outside, 1 meter apart, and she just shouted at my brother's son. My brother looked on. Kid almost cried but didn't.

I'm currently trying to imagine being my brother. As a father, is it ok to watch your wife discipline your son? Does it not erode trust in the father-son relationship?

Son is supposed to grow up becoming like his father, and he is being humiliated before him by his mother. Does it not cause a rift between father and son?