Strange reoccurring reactions

Any two people, but particularly siblings, will recall the same incident differently. It's called perspective.

Thank you for responding Candid.

No. What I’m referring to is definitely not perspective.

It’s some type of unsupported assumption that she is causing, or has caused, a negative feeling, anger, discomfort, annoyance, etc.
possibly a projection?

Another episode is when I assisted her for a work project she had warned was going to be difficult with long hours. She inaccurately recalls me having complained incessantly when in fact I had never done so at all.

A commonality in these episodes is her being helped or assisted in some capacity.

She is a very independent individual who has been disappointed by many and has felt that there’s few she could depend on. Including our parents and her partner.

Even as I write this pieces are coming together.

What she’s doing is completely self constructed and she uses it/ brings it up, as a point in argument.
“Like the time you were helping me and ...” Again. that never happened.

RacerX wrote:It’s some type of unsupported assumption that she is causing, or has caused, a negative feeling, anger, discomfort, annoyance, etc.

Which of the above inspired you to write about your sister here?

What inspired me to write is this latest event regarding the mail. It was hurtful and shocking to learn she had, what was verbalized as resentment and a false recollection. I’m concerned about her mental health.

My sister and I have a great relationship but this has been an unsettling observation I’ve made over the years. We rarely have any arguments but when we do these strange fictional recollections are weaponized.
It feels delusional and a creation to satisfy something that makes her uncomfortable.
Furthermore it’s strange her observation or recollection is never mentioned until it’s used as an weapon in an argument. Sometimes after months or years.

RacerX wrote:My sister and I have a great relationship

Do you think she would say the same?

Absolutely

So you've told her you're concerned about her mental health?

Not yet.
I have responded to her false recollection of events but to bring up mental health during an argument would likely not be taken objectively but as an attempt to gaslight.

I’m considering writing her, how to word it,
and when would be a good time to present such a letter.

Never, given what you have to say about her.

No. Because we really don’t have too many arguments and otherwise she’s a very smart, responsible, and healthy person. Again, It’s only come up during arguments and has given me pause but now I see a definite pattern of behavior.
Just today I recalled another event.
We were both traveling a few years back.
Her in Europe and myself in the Middle East.
We decided to take the opportunity to see each other and visit Istanbul for a week.
About the third day she got food poisoning and confined herself to her room. I made several attempts to stay by her side, keep her company, make her comfortable, get her anything she’d need. She constantly pushed me away. After we had returned home and some time had passed she again had a completely different recollection of the events. That I abandoned her, was unsympathetic, etc. Of course all this only came out during an argument much later.
Her fabrication of events is surreal.

The only analogy I can make is if you borrowed money from someone and then then you repaid it as was agreed and everything was perfectly fine.
But then later, during an argument, they claim you didn’t pay it back or you somehow cheated them.

I appreciate your correspondence.
Writing this out is giving me clarity.

RacerX wrote:she’s a very smart, responsible, and healthy person.

Good for her. What's going on for you?

So I had the conversation with my sister and it did not go well.

I wanted to write her so I could be more articulate and concise but we were discussing the previous event and she just wanted to move past it. It seemed a good time to bring up my concerns but I was wrong. She wasn’t very receptive and got really defensive. I was very calm and let her express her feelings. She made comments about never asking me for favors ever again.
I should have stuck to my original plan to write her.
I have continued to do some searching online and feel I might be coming closer to an understanding. Psychology is so complex I wonder if I’m applying my findings correctly.
I was reading about the Dunning-Kruger effect and other cognitive biases and see a relationship.

My sister who confides in me had told me how she can’t depend on anyone. Not even for the smallest of tasks.

Looking back I can see how she had been disappointed by those who traditionally are supposed to be her rock. Father, mother, husband, friends, etc.
So when she previously asked for my help in things she does so with an expectation of being disappointed. But that disappointment never happens. At some point, either during the event, soon after, or during an argument she subjectively creates her own reality that meets those expectations.

What are your thoughts?

RacerX wrote: What are your thoughts?

I'm not sure why her false memories are the main issue. Why does it matter so much? Is there some reason you cannot accept her interpretation of events, her memories?

As a hypothetical, if you had a member of your family with dementia, what would you do? People with dementia have a lot of false, inaccurate memories. There is no treatment. There is no writing the person a letter or having a conversation to help them remember. They can't go to therapy. If you do tell them their memory is wrong, what purpose does it serve but to cause angst, strife, disagreements, etc.?

I think your best approach is to accept your sister for who she is and to adjust your behaviors accordingly. If you believe her memory is subject to negative and incorrect interpretations, so be it. There is no "fix" that has her accurately and positively remembering events the same as you.

I do understand the desire to help a sibling, but I think there is a limit to your role. From your posts, it sounds like you want to find a medical or psychological "fix" for her more than you want to find acceptance for yourself.