Here's the conundrum from my experience for which the 'answer' eludes me. Even when standing in 'your truth' with a situation, your (non-ptsd) perspective is twisted back as gaslighting them!
Given as example: Trying to point out to her that she is living in an ongoing battle zone of sorts, one that is causing so much pain and suffering to all the others in her life for whom she is emotionally unavailable because of her having to constantly deal with us through a fog of expected perfection because 'she's already dealing with so much with her abusive mother', and trying to point out that her perspective (being one of 'I can handle it. I'm used to it') may be skewed because of the attachment leading her to defend her perpetrator and not fully understand how badly it has affected her, and is still. Pleaing for her sanity, happiness, and the urgent importance I see in her getting out from under it, in order to be able to deal with the 'happy' part of her life with us, as opposed to being always busy being her nagging, verbally abusive, controlling mother's gopher and whipping post - it is turned back on me, as I expound on the theories of the compounding problems linking to her lifetime of 'not seeing it clearly' because it's something she has lived with all her life, puts a different 'lens' on everything - and that she needs to get out from under it.
It turned out to be a several days, ongoing, enlightenment for me, seeing so much we had been dealing with all pointing back to her abuse from her mom and her steadfast stance in keeping herself in the position of sacrificing her life for her mother, just like her mother wants it.
I am paying still, to this day, for my encouragement and attempt to enlighten her to her stance and the harm she is doing to herself and her other circles of life by staying there, under her mother's constance stress, demands, and degrading abuse -- to now have it be a point of reference for her to show me how "controlling" I am, how I'm "same as Mom" - just that I go about it "nicely", but that it is "abusive" on my part, just trying to get her "where I want her" so I can "be happy, whether [she] is or not", and that I will "never understand" because I "need help". I do need help - she is right about that - because the circle of (non)communication is "crazy-making"!
Any advice? How to deal with anything that would possibly be effective for change or help, when it is all twisted to such an extent that her friends, who hear of my - what's now called "abuse" of her - all from her perspective only, are encouraging her to get away from me - and even I myself keep questioning, rethinking my own ways, and intent, even when I know I have nothing but love and good intentions. How to ever break the cycle? Give up? No answer? Do we (non-ptsds) just leave them (c-ptsds) in the "bed" they're making for themselves......although your "bed" will never be the same without them?
It's so frustratingly sad and helpless-feeling knowing they are such a wonderful person who is just throwing away, out of their own skewed mind-set, such an authentic chance for 'real life and happiness'! She would, no doubt, say I am the gaslighter, and she the gaslightee, and be very effective in making it seem so.... (even writing this, I continue to test my motives for integrity... yet I know they are clean...."yet, are they?...yes, they are...well, think about it...no, stop questioning yourself..." etc. Makes me feel crazy.)