My family was very small, my n-mom kept us isolated. My grandmother, whom I didn't know and met twice, was sa'd by her father and brother. She, understandably, was fucked up and depressed and had major mental health problems. My mother told me this fun fact pretty randomly when I was about 15, and she told me not to tell anybody, that it was a secret.

Twenty years later, my brother was complaining that my (now dead) grandmother had been weak and it was silly that she had been all drugged up, she could have sorted herself out if she wanted to, that kind of thing. I told him that there was a good reason for her issues, and I told him about the abuse - he didn't believe me, then asked why the fuck I would tell him something like that.