The thread starts here...
In the middle, Ginnie discusses how family members who wake up to the family dysfunction usually try to handle it. If you're the family truthteller or scapegoat, you'll recognize this:
So if MIL [mother-in-law] has any kind of support/enabling network, she's not likely to profit by therapy. Because as pointed out it's not really her, it's you who has the problem--EVERYONE says so. Right? She won't be motivated to treat therapy respectfully. She won't see it as fixing her to alleviate her unahappiness, she'll see it as fixing you.
So to make therapy work you have to deprive her of her social support system. Which is a crazy-making and actually very controlling thing for you to do (controlling because you think you have a say on other people's relationships). But people try. Rather than change themselves, they decide MIL (or DIL [daughter-in-law]) needs therapy, intuit that as long as FIL, SIL, DS [dear son] or whomever is supporting the targeted dysfunctional person that therapy won't happen or work and decide what needs to be done is to convince everyone what a mess MIL really is.
You see DILs do this by starting with their husbands, "Your mother is ___". And they complaint to their siblings in laws, and their FOO [family of origin] and other ILs and friends, and hope to influence other people to see MIL the way they do. They honestly think they are revealing the truth and being helpful. And maybe they are right, but it's never helpful and doesn't work, because people have their own opinions, experience and needs with the MIL and aren't going to borrow trouble. Not only that, while the DIL is recruiting people to see MIL her way, MIL is recruiting those same people to see DIL MIL's way. It's a horrible mess, doesn't work and causes far more problems than originally existed.
The only way to cut out MIL's social support system is to completely withdraw from her, thus changing everyone's experience of MIL--this takes a lot of time and doesn't always work. But this is how it works. DIL is married to the prime MIL enabler. She completely withdraws from MIL in every way, a cut off. This is called 'removing the buffer'. Now DH's [dear husband's] experience of MIL changes as he becomes the target for MIL's dysfunction. He doesn't like it so he withdraws. Now MIL (after escalating and trying to force DIL and DH back into their roles) has to find another target, so she starts focusing on her second son. He's used to his brother taking the major heat from MIL, and resents this. It feels unfair of him. It has changed his experience of MIL from being annoying but tolerable to being impossible to deal with. So his first act is to put pressure on his brother to resume his MIL buffer role, if that doesn't work, BIL now withdraws. So MIL finds another target for her neediness/dysfunction/whatever. It might be FIL, a sister, a best friend...
But as the enablers disappear out of MIL's life, her crazy gets worse (because she's more and more scared). However, it can take between six months and 5 years for an enabler to completely walk away and mean it. Typically there is a long period of cutting of and 'trying again' a lot of guilt, a lot of escalation and promises and other games. If a MIL has 4 enablers in her support system, it may take 10-20 years to get her to the point that EVERYONE has 'abandoned' her.
And it might never happen. New people show up all the time. A new 'friend' at church, a reconciliation with a distant sister, playing one relative off against another.
The technique Ginnie describes is known elsewhere as "dropping the rope." It's useful in situations where you're getting a disproportionate share of the strain of handling the disordered person. For example, your husband doesn't want to deal with his mother, so he uses you and the kids as human shields, and because his mother's generation expected the wife to be the social secretary, your mother-in-law thinks it's perfectly natural for all contact to go through you. You can't stand your MIL any more than your husband can, but he refuses to back away from her because his experience of her is manageable--or at least, it's less painful than a cutoff. He might even claim you're making your MIL's crazy up.
So you drop the rope. She's his mother. He can make plans with her. He can call her every week. He can deal with her constant demands to Skype with the kids and her weepy guilt trips when he tells her no. You set your own boundaries, and let him deal with his mother in any way that doesn't violate them. In the in-law forum I read regularly, it often takes less than two months for husbands to come around and start cutting out their toxic family members on their own. All you need to do is let the people you're sheltering feel the strain.