Unnamed daughter[]
Their is not that much information about her,but,she is possibly mother's child,when she was in a relationship with her unnamed husband.
She could possibly be Amanda,the girl little boy fell for,and their is something to back this up,because,just like mother,she had a boyfriend,and while going out with him,she tried to cheat with little boy,which started the rivalry between little boy and school kid,but,it could just be a hoax.
Unnamed brother[]
The daughter had a brother,not that much is known about him either.But, he could be the boy, that little boy was talking to,when telling the story of how little boy "got rid" of school kid