Hi Jeanie,
First of all, I am sorry that you have had to go through this with your daughter-in-law.
I would never ever ever talk to my mother-in-law or mother in such a way. However, with that said, my mother-in-law and father-in-law have very limited roles in our lives because of THEIR disrespect. I cannot possibly get into everything that they have done (down right insane and evil with a lot of their actions!!) Even with this, I would never use poor language with them....I just let my husband deal with them and I limit their involment with our children. The reason for this is because of how horrible they have been and I feel, with my children only 2 and 3.5, I have to do what is healthiest for my babies. So, I guess I can say that I live both sides of it....I would never treat my mother or step-father (in my mind, my real father) in such a way, but my inlaws do not deserve respect that they refuse to give themselves. Does this mean that I carry on and throw out disrespect myself?? No, I ignore it and I will still email them pictures of the kids and I definitely have my children call them to thank them for gifts or just to say, "Hi!". They live in Texas and we live in Missouri so this keeps problems at a minimum.
I am sorry that this is happening in your family.
Tammy