I'm NT and, after my mother died, finally went no contact with my profoundly narcissistic and histrionic father three years before his death. It was the best thing for myself, husband and children, and yes, it was hard to do on some level because it is adverse to social "rules" and expectations.
It saved me from his constant, unrelenting emotional abuse and gas-lighting by him and my youngest sister whom I believe has borderline personality disorder. I have cut her and her family, too, out of my life in recent years. I don't know if being autistic makes it any easier to walk away from abusive relatives but there are family dynamics and mental illnesses that override social conventions. Other people will not understand why people like us leave because they have not walked in our shoes, and they remain subject to the BS manipulation that flows from the toxic relative(s).
I'm still close to my younger brother and middle sister but I avoid bringing up the topic of our father and little sister. They know how our father was, how he treated me, and they can lie to themselves if that is their pleasure.