If she was concerned about that sort of thing she either wouldn’t have a Facebook account, would have a locked account where people wouldn’t be able to contact her, or she would use an unidentifiable account. My mom is a T and she uses Facebook to be in touch with family but only her contacts know it’s her. It’s not searchable.
My T on the other hand SHOWS me stuff she posts sometimes, contacts me to send me articles through messenger.. we are not “friends” on it but clearly it’s fine with her that I can access and see her account.
They choose their boundaries and the nature of social media is such that it’s social. If yours was super concerned, she wouldn’t be on it.
My T would be glad someone contacted her through any means if they felt i was in danger. Give yours (and yourself) a chance before writing everything off.