My parents and I never discussed it, though my sister told me they always knew. They told her about me being gay right after I enlisted in the Army in 1969, age 20, more afraid my fellow soldiers would slaughter me than the Viet Cong would. So strange -- it seems everyone in my family knew I was gay but me.
And while they pressured me to meet a "nice girl" and get married, perhaps a curative, when I finally caved to them at age 29 they again told my sister they feared I was making a mistake, not being "husband material." After years of nagging me to do just that! Parents!
And they were right, the marriage a total disaster. I asked my sister afterwards, when I learned of all this, why hadn't anybody told ME? You all talked about my being gay behind my back, you didn't try to block this marriage, you just sat back and let me make a BIG FUCKING MISTAKE??? Fine family YOU are!
I had a BF who wasn't "officially" out to his parents, but he told me his mother knew. She just wouldn't discuss it. But she liked me, knew about our relationship (in fact she once interrupted our having sex, a funny incident I made into a short story), she even bought me Christmas gifts. And my BF told me she preferred that her son had me for a companion, because I was so "butch" and gave him an aura of masculinity he lacked (he really was something of a flamer).
If her son associated with me, an outwardly masculine guy (at least compared to his usual fairie friends), then she thought some of it would rub off on him, and dispel the rumors she knew were all over town. His ex-Colonel friend made him sorta legitimate in her mind.
And I never knew how to accept all that, and always wanted him to just tell his parents (I was over to their place for dinner at least once a week, or went out somewheres to eat with them), but he never would go near the subject with them. So awkward for me, and really so unnecessary in my judgment. But it was his agenda to control, not mine.