MIL issues.

Oh boy here we go. I honestly don't know what to do anymore, my MIL has never liked me (which is fine, I don't particularly like her either). She manipulates everyone in the family, always has a huge issue with someone and then acts sugary sweet to everyone else at the time. She prefers her older grandchildren over our kids and is pretty blatant with her favoritism. Because of covid, we let her and all the other family know we would not be having people around our newborn. Immediately after she was born, MIL repeatedly asks to visit, my husband and I took turns responding to tell her we still weren't having visitors each time she asked because if I tell her no she always goes to him next. Time went on and we slowly started seeing people. She lives an hour and a half away and the people we were seeing live in our immediate area with the exception of my brother in the army who surprised me with a visit. Next, my sister who is in the air force was granted leave so she came to stay with us. We dont have parents, mom is dead and their dad is in prison so we are very close. We had plans to go to the beach for Halloween and could take a route where we could stop to see MIL so we asked if she would be home, she had to work so we told her we would come next weekend.. After we got home she texted my husband a huge rant about how she can't believe we are punishing her and that she's sorry she didn't take him to the dentist more as a child (last time we saw her in person they were discussing dental work they both had to get done, this was like 6 months ago). Husband told her she could not manipulate him into coming sooner and explained he was confused since they talked the day prior about us coming next weekend for a visit and that seemed to be okay. She just cried and admitted she was trying to make him hurt since she was hurt. She did a video call with our 3 year old yesterday, and today is posting passive aggressive things on Facebook about people controlling who others talk to being DV and that if "you're the keeper of the box, you're going down" which I take to be directed to me since she likes to blame me for my husband not talking to her more. I really don't tell him what to do, he's grown and can talk to his mother whenever he wants, it just happens to not be that often because of the drama. I just don't know what to do anymore, I just know that I am fed up.