Surely posting this for the permanent internet to see forever will eventually get back to her or your Dad. Maybe some private discussions among the family won’t make her or other family members feel betrayed or wonder if they should ever trust family again.
No they’re not on social media
Good that you try to protect them. My friends parents got wind of things from neighbors that were implied about them from older siblings or grandkids on Facebook…and what was said behind their backs. They felt a bit betrayed. They hated the rise of social media to tell the world family troubles.