Thanks Jadmack!
During a moment of weakess about a year or so ago, I did sort of tell MIL precisely what you recommended. AH reminded me of how cruel I was for saying those things for a good long while.
And during my melt down of last week and engaging with AH I did point out to him that while I'd grown to expect him to not support me with regard to his family, it took things to a whole new level to see that he wouldn't stand up to them for his daughters either.
And, in following the advice of one of you who pointed out that a r/s with grandkids is a PRIVILEGE and not a god given RIGHT, I have quietly and in one sentence, told AH and his mommy that until I see a change in behavior (actions vs. words) the girls are off limits to his family. AH was dumb enough (or smart enough bc it helps me immensely) to respond and say "that sounds reasonable and I support that".
End of story. There's no way I can be accused (well I can be accused of it but I have AH's own words saying that's fine) of keeping the girls from his family against his will.
I feel such an immense sense of relief knowing a) I don't give a $h*t anymore what they say about me and b) I don't ever have to deal with them again bc I'd bet everything I own that there will never be a day that they own their behavior. And this may come off as if I want to punish them by keeping the girls from them, but really, this is about protecting them. If MIL is as toxic as she is right in front of my face, there's no way I am trusting her to not hurt/manipulate/put in the middle of her hate toward me when the girls are with her alone.
D6 already has had it with MIL and D3 has been all but ignored since birth by AH's family. The only time that they see the girls is when I run around crazy coordinating visits around their schedule.
AH's interest in being a father ends when there is no audience to show off in front of and it appears that his parents are the same. I really don't think the girls are going to be missing much by not having a r/s with them.