Sooo very much this. I sometimes play an imaginary conversation in my head, but can scarely imagine what convergence of factors it would take for it to actually happen. And truth be told, I'm quite sure I don't even want it to. She is very messed up (I'd have to say she has at the very least 3 dx-able things) and it would be a pointless exercise as denial runs very deep on her side of the family (the only relatives I was allowed to know after she kidnapped us when I was 3...'nother story). She is in her 70's. There's no "guess" in how that would go.

So, to your question. Nearly all of my relatives I have no contact whatsoever with.
***I do not speak with my mother any longer (I don't hate. Can't be bothered. The whole deal is just too toxic.), sooo, as I'm sure you already figured , she doesn't know.
***My dad (whom I finally reconnected with at 40, and speak with 2-3 times a year on the phone) I told (what could be the harm, right? Lol.) I wanted to quite some time before I did, because I just couldn't figure out how to work it into the conversation. He was cool about it...everyone's brain's wired differently etc. It's neither support nor non-support with our conversations so infrequent, you know?
***Finally, and to end on a good note, there is my sister. We reconnected (after 20 years) several years ago, thanks to being in therapy(!) I needed someone to verify that it really was like I remember it. It was. (She does have contact with relatives, and assures me nothing has changed but for those that have taken denial to the grave.) She is very different, as in, thoroughly "normal". She doesn't "get" it, but she accepts it and doesn't say anything mean. We IM usually once a week (3,000 miles away, so...). I really appreciate it, as it has come to a point where (besides BF) she is the only person I have anything even approaching regular contact with IRL.

Soooo.... pretty small test group(!), and sure, I skewed the data by excluding my mother, lol, but at least that allows me to not consider support as negative(!)