There are lots of direct and indirect ways to deal with bullies. There are good ways and bad ways to handle them. But when there's an extra element, like the situation here, where you have a nice woman, your mother's friend, who you don't want to hurt, it toally the changes the game.
Also, being bullied is traumatizing. But having to sit at a table with them, when you both know the truth, and pretend everything's okay, I think that would be traumatizing too.