Most Helpful Guy
I think he is going to deal with her the same way he is dealing with your questions about it.
Ignoring people whose business it isn't is a surprisingly effective tool.
Most Helpful Girl
What does he need to defend you from? From what I understood, his mother didn't attack you or anything. Balancing his relationship with you and his relationship with his mother is his business and as a good girlfriend you shouldn't want him to fight with his mother. He'll tell her what she wants to hear, but he'll do what he wants with his money. Mothers in law can be pretty awful, but trying to keep the peace is important.