[quote author=elephantschild link=topic=124862.msg2886685#msg2886685
Oh, I'm willing.

But this is DH's mom and he's not always so willing. He's miles beyond others, though, in that he at least calls her on it, whereas everyone else just seems to roll their eyes and wait.
We had to work to get him to that point.

[/quote]
I think there's a big difference between handling a one-on-one situation, like the original thread on this, vs walking into a long established, but unacceptable, family dynamic. In the first situation, it's easy to start setting better boundaries or simply stop inviting the person.
But this situation is different. You're an in-law, and your DH is accepting the behavior. (calling her on it doesn't count if he doesn't try to enforce boundaries). So it's really tough!
I think the only time you can control things is an event where you're inviting them over, or providing transport, etc. You're perfectly free to proceed without her, but whether it's worth the angst this might cause the rest of them is a different issue.
It has to be incredibly frustrating!