onlyhereforthebiscui
If either is true then the ball is entirely in your court. Have a serious chat with your DC about this relationship, it is clear that they know what both grandparents are like. I suspect that they would be no more enthusiastic about their grandparents than you are. In which case, just say thanks, but no thanks for the invite, for all of you.
After that, do not become estranged, but just put the relationship into neutral, do not cut them off, cards as appropriate, if that is what you do, leave DC to visit as they please, but otherwise do make any effort to contact them.
It doesn't matter whether everyone in the world gets on with your MiL, (which, lets face it is no more absurd than her claim that everyone in the country, or even her road, gets on with her) you don't, and that is all that matters.
Grandparents are not a necessity, they are not sacred. There seems to be a cult of the grand parent around these days. Children will grow up quite happily and undamaged, whether they have grandparents or not and if the grandparents are unpleasant, they are probably best out rather than in.
Talk to your children, reach a joint decision and act on it, and just leave these grandparents to marinade in their own unpleasantness.
Are there any current ads that make you laugh?
