Ok, what have you done to change this for the future? Sure sounds like he's old enough to realize the difference between what he hears and what is appropriate to say for himself as a member of your family. Respect for others, and fair fighting and all that stuff...you could go in any of those directions or all of them.

While disrespect for siblings is considered normal, it doesn't have to be long-lived. I fully believe the problem of today's youth is lack of respect, lack of self-respect too (thus what others call low self-esteem.)

You have a prime opportunity right now to give him and your daughter a better way. Good wishes!

(Maybe your spouse will learn how to be respectful along the way too?)