Yes, SL... those moments when your family interactions seem to be opening up into the "rational" universe again... those experiences for me, have always been a combination of what the website calls "intermittent reinforcement" (sort of a pretend validation) and "hoovering"... getting sucked back into "playing the game; reliving the old scripts" again. But, I would suggest that ordinary personality (not necessarily PD) also plays a part in this. Some people, normally, avoid conflict for instance... anyway they can... and it's not a PD symptom. And, yeah -- sibling rivalry and those old scripts are going to rear their childish heads, for sure...
it can be a minefield, for me. Part of me wants to believe that I'll be the beneficiary of some cosmic miracle... and wants to believe that my family has changed. Desperately wants to believe this. Stubbornly. To the point of my own denial, that in 40 years... they're still the same. Mom and Bro. That may also be a bias of judgement... in the other direction...
so what I've come to realize is that I've got to have an inner boundary between evidence and observation of their behavior that I can verify and between my old hopeful wish and belief that miracles can happen. Because that believing part of me is giddily, deliriously, oblivious to the evidence... that for 40 years, every time I've trusted in those moments of pretend validation... it's always turned out badly for me. I can't stop being who I am, any more than they can stop creating the same old pathetic, blaming, catastrophic situations with no-win circular arguments... but I sure can control how I behave in what I know for a fact, is a dangerous situation for me. Keep my distance, watch my back... and while trusting in God, I'm still gonna tie my camel!!
I'm allowed and that doesn't make me a bad person.