I don't think my brother will tell my dad, as he's very adamant about keeping most things private and separate from my parents. I doubt he'll want to open this issue up to my father, although he may very well have implied it to the rest of the staff. He was definitely questioning the office manager today about having said anything to DD about "someone coming by the house to check."
The thing about ODD is, she has an incredibly memory for conversations and imitations of people. Over the years, I finally learned to believe her what she said said about people's attitudes. She can imitate her teachers so well that I can barely drive for laughing so hard, and she could imitate the ballet director so well it was like watching a possessed person. She's just really perceptive and good at remembering conversations. So if she remembered the office manager making a comment, it's more likely that she remembered it, and the office manager would either not remember or deny it because she needs her job.
I wish DD had the kind of grandfather who would take her side or at least listen calmly, but my father would just get embarrassed, and hold it against DD. He tends to favor YDD over ODD because YDD is outwardly much more "perfect" than ODD. It is very obvious to us (especially ODD, with her people skills) but I doubt that my father is even aware of it.
DH thinks it will all come out eventually, (thank you, Little Miss Ray of Sunshine) but I think that it won't, other than future issues such as ODD's wedding or college graduation, etc, which are too far off to worry about now.