Just venting. Advice would be awesome!

My MIL has been a crappy mother to my husband since he was in middle school (that was when she decided to have an affair and neglected her children while she was at it). My husband would still talk to her, but the past 4 years she’s been completely ignoring our children (not even acknowledging the last ones birth or the current pregnancy), she refuses to contact my husband which hurts him bc he doesn’t understand how a parent could not want to contact their own children/grandchildren. 1,5 years ago I contacted her at informed her of our feelings, called her out on her actions, etc. she then had her husband call and text us instead of her (he was saying I don’t know why you all feel this way, or I can’t believe you have these “ill thoughts about your mother in law”, etc.) then she would contact Ryan every other month saying that he needs to find it in his heart to move on bc she has done nothing (even though she has done every hurtful thing). I messaged her 1 year ago and got my husband to talk with her to hopefully mend the relationship (since she would randomly text him, “thinking about you and your family. Hope we can have a relationship again”). She apologized, admitted to being a shitty grandmother and for hurting my husband so many times. She started texting my husband 1x a month to say hi. He would respond back, but still refused to talk to our children (who are all under 9 btw and have done not a single thing but be wonderful and kind and sweet). Now she’s back to ignoring completely...no birthday calls/cards, no holiday calls, hasn’t done anything or made any calls/txts for around 6 months. It breaks my heart bc I know that my husband hurts bc of it and I don’t get why she wouldn’t try to have a relationship with her own grandchildren. I have a feeling that she will end up randomly sending something small on Christmas or nothing at all and how my husband is going to react to it. I wish I could just push her out of our lives and not think about her bc of the pain she puts him through. I feel like sending her another message stating (in a respectful way) that ‘she ruined all possibilities for a relationship now. I tried to help her, but it seems like she doesn’t care enough to have us in her life & to not bother contacting us again (not like she was planning on it)’ BUT I won’t contact her. I just hate how she will randomly pop up at Christmas but ignore the rest of the year and hurt them. I just want her to be in OR out of our lives and to stop playing games. This also effects our relationship bc my husband will get on edge and take it out on me around the holidays.