I don't think Joanne's home with either of her parents was very pleasant. Seems the home was violent and Joanne's mum drank heavily to "cope" with that.
Margot Curtis
Joanne’s mother, now deceased. Margot had a fractious relationship with Joanne, and she drank to deal with her difficult and violent home life. Following Lyn’s disappearance, Margot told police she did not think her daughter Joanne was in a romantic relationship with Chris.
John Curtis
Joanne’s father. John said Margot told him of the sexual relationship between Chris and Joanne when his daughter was still at school. He asked Joanne about it, and she denied it. John never confronted Chris Dawson, nor reported the sports teacher.
Nocookies
The Australian - December 5, 2018