show your child by experience how to handle this as an adult, they are watching every move you make right now taking mental note of how you are handling this as an adult and even if you dont know it yet they are learning how to respond by your actions.

your missing the point in all of this, its no longer just about the child or childrens reactions to each other in that cutthroat world we has adults call school, its mom and mom bickering as well making it worse.

there never going to get the opportunity to work this out between themselves because of each others parental prejudicial view, not there own.