My ex has actively alienated my eldest (14), since the year has past I have had a bereavement, and a terrible family trauma of family members. My eldest doesn't show any emotion to these things. She copies her dad.
She is still disrespectful to me and blocked off my side of the family. This can be selective depending on her mood or if her dad or grandparents say anything nasty again. But my sweet girl has changed so dramatically.
How much of it is teenage.. separation... her personality.... etc. nature/nurture..
From what I know.. a child doesn't naturally choose to completely shut off a parent. Not only a parent but the parent who hasn't ever let her down. Has always been devoted and continues to do so.
It's so hard keeping boundaries as she's not broken our trust, I'm also called bipolar if I try to keep boundaries (ie; tell her it's unacceptable to speak to me rudely)