In the car I said, "Look. No one in this family has any right to say anything to another member of this family that hurts their feelings, intentional or not. And if a member of this family does hurt another family member's feelings, they need to make it right." I was actually pretty proud of myself for coming up with this because it took the focus off the fight and made it more of a "family rules" issue. And there is no way to argue with that.
So he said, "Yes, you're right, I could have worded that differently." Etc. I told him this was the level we needed to be working on. Not sure what he thought of that, but that pretty much ended it.
Good job!! That is great progress, and I'm really proud of your ability to stand up here! The fact that he recognized it and agreed with you is even better. Keep going!