Overstepping MIL!/ MIL from h**

SOOOO my MIL announced my pregnancy before I did on Facebook! She’s one of those social media show people , she loves trying to have something to show. She was never really in her son’s life! Her mom raised him. Now she’s trying to tell him how to change the spelling of the name we have. I just dont know what to do… or how to even react? Can i get some advice please …. She was also mad the he told his grandma ( the woman who raises him) about is being pregnant before her! She’s so petty! And lets not forget before the baby! Me and her had some issues! And we weren’t speaking!