My boyfriend’s mom

My boyfriend is a little bit of a mommy’s boy. As in he does what she wants and won’t stand up against her. We went through a rough time in our relationship while living together and when we worked things out, she said she was washing her hands of our relationship and not dealing with it anymore, then continued to say some rude things about me. She’s always been borderline nice/rude to me but now she’s just rude. She got pissy because he didn’t get to see her on Christmas even though she didn’t mention anything of it. And if he doesn’t text her back fast enough, she’ll get mad over that. Anyone dealing with an in-law that you really don’t like? How do you bite your tongue when you want to speak up