Yes but this is one of those things that could end up being a mother in law- son in law issue whose shalom bayis ramifications far outweigh the rudeness. What matters most is keeping the peace and not starting a conflict. If your daughter is not complaining why bring it to her attention? If he is doing it to a point where it is obviously rude, a rosh yeshiva or an employer or a good friend will tell him. From your daughters perspective, she would most probably wish to believe that you think he is the best guy in the world. Pointing out a fault of his magnifies it in her eyes and begins questions that she may have never thought about: Is he really a rude guy? Do my parents not like him? Why am I with this rude person? What is with my mother? Why does she have to nitpick on my husband? What kind of fight am I going to have to go through with him the next time my mother invites us? Now he has a built in excuse not to go-your mother thinks I am too rude for her table….
Oy please! This can’t go anywhere well. I believe in the in law golden rule: Shut the mouth, open the wallet! NEVER MIX IN!