Long story short, she doesn't know I figured it out, her source of trauma is that I was born and I just want to make sure she doesn't suffer further. 

Also, I'm really really really sorry if this is triggering to anyone and if anything I write is insensitive, I really don't mean it, and please let me know so I can think about it and maybe fix the wording so I don't trigger anyone... so... 

(also pls let me know if I tagged this right I don't get the tags in your sub yet haha sorry) 

Now the details. 

I'm from twins, unpreferred one and only in recent years began to realize just how deep my childhood trauma runs. Used to break the fight at home (my father probably was mentally ill, we'll never know, he's now disabled mentally and physically), there were suicidal threats and knives involved. Emotional caretaker for my mother, yada yada yada. My trauma fits CPTSD more than BPD and I know these two can get misdiagnosed and I just started therapy. You can check my post history for details I guess, I'm on CPTSD sub quite often these days. 

Now. 

My sister caused some of my trauma. She used to belittle me for everything I did when I was growing up as well as in adulthood while I was still in denial. We have an extremely complicated relationship. Last year or something like that she screamed at me I should have never been born, which sorta unlocked all the memories of her (and my father) causing all the damage. Fun times. 

Now I don't want to share too many details about her for obvious reasons but - my family (me included) prevented her from attempting suicide a few times in the past two years, she's in therapy and on medication luckily so things are getting better for her. She's got huge emotional outbursts at times that must be really tiring, she's an impulsive spender (after these outbursts to make herself feel better), overeating, and obsessive sometimes. Mood swings like it's the high time at the playground. From the outside, she seems to be manipulative and mean. 

She's also extremely intelligent and really doing her best. She's driven and details oriented, really admirable. She's good to her friends and really fun to be around with a great sense of humor. People do generally like her, I can tell from her interactions at work. 

IDK how about others in the family, but I know that no-one figured out she's BPD, just me. Everyone thinks she's "plain crazy neurotic" or something like that and since mental health awareness in my family is frankly shitake, I'm not really surprised. I'm stereotypical, kinda - I do like studying psychology and reading a lot about that. Long-term social, now I'm concentrating on some basics of psychology course to give some base to all the books I read already and I'm fascinated by neuropsychology. I did research on BPD and I really made sure I'm not slapping a sticker on my sister's forehead in my mind and considered if maybe she's Bipolar, also CPTSD, highly neurotic, or some combination and I'm fairly certain I'm not wrong with the whole BPD thing. 

She seems interested in fixing our relationship, and I think that it might help her as much as it might help me going forward, and I've put some boundaries for myself in place, but she doesn't know I figured her BPD out and I'm not sure she knows I have CPTSD (her being part of the cause the conversation frankly is not on the table for now nor in a close future). 

So. I want us both to get better, but she's got it worse (and I don't mean to compare or be like yay look I'm better, but she's got it much harder on herself). Is there something I can do? Like some support, I can offer? All I can think of are the little things - got a cool dress with motives of our favorite cartoon for her baby doll recently, I always try to talk about her interest when I get to participate in it separately and got something to share so we can talk a bit... She played a really cool videogame yesterday and I liked it and stayed watching a little longer because she enjoyed describing and explaining it (I had my own video game to get back to at the time but ya know what, I might get that thing she was playing, it looked kinda cool and relaxing). It's all just little things, is there something greater I can do? Is it even a good idea, seeing we're both each other's past pain sources? Ideas? Tips? Anything?

Sister's therapy is off the table for now, I'm not ready for that. I'm barely coming to terms with the fact I did start therapy, still got a lot to process.