My 12 1/2 yr old great niece used to be the really loving daughter to Dad. They got along great until a few months ago. Mouthy, sassy, saying deliberately hurtful things to Dad. (I'm Mommy's girl, not Daddy's girl, etc.) Started her period a couple months before that. Dad doesn't want to be around her, same for her regarding him. Are these raging hormones or someone who needs straightening out? Suggestions for improving situation?