Dear Richard Madeley: My family is being held hostage by the whims of my wife’s controlling sister

She clearly suffers from a personality disorder of some sort, but her cowed husband won’t intervene

I am increasingly concerned about the effect my wife’s elder sister is having on our family. Her domineering, controlling behaviour and negative approach to life have taken a heavy toll on her husband – a lovely chap but a gentle soul – and their children, to say nothing of my wife, myself and our brood. On the few occasions anyone has taken issue with my sister-in-law, she has turned the spotlight right back on her challengers, saying they are the ones with a problem.
It has been clear to me for some time that she suffers from a personality disorder of some sort. My wife and others involved are now beginning to agree with me, but we realise that unless our brother-in-law is prepared to take the lead, any attempt to stage an ‘intervention’ will be ineffective. He says he doesn’t want to ‘stigmatise’ his wife, though he is also quite simply cowed by her. Meanwhile, the problem is escalating, and our nephews and niece have confided their own concerns to us about this. 
My question is: what now? We’re effectively being held hostage to the whims of her mood swings and obsessions, yet the one individual who could and should make a stand shies away from doing so.
— Anon, via telegraph.co.uk
What now? I think you should tread very carefully, and be certain you don’t make your brother-in-law’s life any more troubled than it is already. Although I agree with you that it would be better if he came on board, there’s absolutely nothing to stop the wider family from simply bypassing him (which is probably what he wants) and dealing with the problem as a group. 
Of course, I have to take your analysis of your sister-in-law’s behaviour at face value. Your letter is all I have to go on. Therefore, assuming your diagnosis is fair, and not driven by personal dislike and/or disapproval, you must marshal your forces and take collective action. 
I don’t recommend some sort of face-off or direct challenge. That might come close to the kind of bullying you accuse her of. No; what you must all do is agree to jointly resist these unpleasant whims and manipulations. Agree to fully support each other in this. From now on, when your sister-in-law attempts to control or dominate any of you, simply explain to her, politely and without heat, that the family is concerned about her and her behaviour. Then withdraw from any further confrontation. 
Once she realises that she has lost the power to manipulate you all, she may become reflective. That is when her husband can play his part, and gently encourage her to consider counselling. 
There’s no guarantee any of this will work – but if you are being honest with me, and there is general agreement amongst the family that you are all being bullied, then you must stand up for yourselves. And cut her husband some slack. The poor guy is stuck right in the middle. It can’t be easy for him. 
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