Dealing with manipulative people

[CornishMade]

I’m wondering if there are any online resources or help sites to give advice about dealing with manipulative people… in general, not solely about men who don’t want their partner to leave them.

My DB left my SIL; last year. They weren’t married but have been together for years. Two kids.
DB announced this out of the blue by all accounts and in the months since, everything has gone downhill fast in terms of civil communications.

SIL called me to talk about it (she told me before DB did) and we’ve been in fairly regular touch since, with msgs and when we call, long long calls. For context, I’m living abroad so haven’t been able to visit or be any practical help beyond listening and sympathy, though I’ve offered to help with any online research or whatever she doesn’t have time for.
She’s got many good friends around her local area which is fabulous and I’m very glad of that. She talks to them a lot.

She asked me the other day to see if I could find any information / advice on dealing with manipulative people. DB has shut down from listening to her, it’s his way or the highway etc when it comes to finances, the kids. With hindsight she now realises he’d stopped listening to her / engaging in conversation a few years ago, if a debate or argument came up at home. But of course it’s worse now as they’re living apart and parenting differently and sorting out the house and possessions, and she feels he’s being very manipulative.
But I’ve had a google around and advice articles or websites seem to be based around the woman escaping a controlling husband, whether she’s planning to or has done; and he wants her back; keeping records for court cases or police etc against this man who’s annoyed his partner has left him. Which isn’t the right type of information when SIL is the one who was left, against her wishes, although she’s now gone from being devastated to hating him for the way he’s treated her over the past few months.
Other sites I found were like Gingerbread but that’s practical living advice it seems, finances and housing, rather than dealing with manipulative people.

Any pointers?
Or maybe I should prompt her to post on here herself for support…

I haven’t talked much to DB about the situation. We have talked, of course, but he has hung up on me when I started to say things he didn’t agree with, which had never ever happened before. I’ve talked much more to my SIL; calls with DB have been more general, not about feelings or practical details beyond his ‘headlines’. It’s like I have two DBs now. The “old” one I was close to and don't want to actually fall out with forever, and the new arsehole one who’s treated SIL horribly.

I find it quite strange that with all her good friends, that she talks to a lot, the person she asks to research manipulative people is her ex's sibling. Is she incapable of using the Internet, Do you need find that odd? You seem to be taking everything she says as gospel. And in turn painting your brother in the role of villain without actually finding out his side.

I'd be concern you are the one being manipulated. She's totally leading the narrative here and you seem very willing to accept it. Is there a back story with your brother and your relationship here?

I agree with @Thingsdogetbetter. Sounds like she's playing you. She could just as easily google what she's asking you to look into. I suspect it's not just your DB that's being manipulative here.

Ok, I do hear you - I am very aware that I'm mostly hearing her side. But it's mostly about her feelings, when we talk. Like I said, I want to "keep" my DB, I'm not falling out with him. And I have heard his side, he's just much less expansive... or upset...
No backstory with my DB, we've always got on very well incl staying for visits when 'home' from where I live now.

The major points of DB's leaving are known and SIL is not making up those facts, DB has talked to me too. For example about wanting to introduce his gf to his kids cos he's fed up with pretending he didn't leave for s/o else. He's now trying to engineer doing that earlier than he'd originally said he'd do.
Financially DB is doing more than legally required (thank goodness) given that they weren't married. But it's not 'fair'. So it's stressful.

Yes she can google, and she has friends, but we are also close and she's chosen to talk to me sometimes too. We're her family, it's been decades.
She's also completely exhausted from the past year, with a surprise separation which was initially devastating emotionally; then dealing with all the practicalities of a split after decades including house, new house, money, childcare while he's being self-centred; plus lockdown, home schooling, kids upset with the split, on top of her own job. Very isolating and overwhelming.
Some things can remain on to do lists for weeks can't they. They do for me too and I'm not even in that situation - 'this evening I'll definitely look into xyz' and then the evening comes and you just can't muster up the energy.