It appears that your mom feels she has a lot of power in the family, something that is very hard to make go away. Are you maybe, a little afraid of her? I was of my parents, even at the age of 45! That was pathetic.

I think you're going to have to take a stand and tell her you don't want to hear anything negative about T because you like her. Or, you could just stay silent and she will get your message by no response. But, I would take the response path so she will know exactly where you stand.

Maybe not have mom and T at the same gatherings, if possible?

When my oldest son got his girlfriend pregnant, my dad called me and said awful things about the girl and was blaming her for the pregnancy. I just listened and when he finally asked me what I felt I told him that my son should have kept his pants zipped and he was just as much to blame as the girl. He didn't like it and my parents have said negative things about my son's wife and I just tell them...well, I like her.

Sometimes, it can take just one person in a family to change the negativity and it might be you!

Good luck. Not a fun thing.