My question is: Why was this mother FB friends with her principal?
I have one social media account for my personal life and one for my business life. Sometimes the business side flows to the personal side, but never the personal to business. On my personal FB account I also have groups set up and only post to groups that I want to see something.
I'm not trying to blame the victim here, I'm just trying to say that we need to use some common sense when posting things on social media. If you wouldn't say it to someone's face, don't post it where they can see it.