When abuse done to parents by their child. When parents keep denying lines have been crossed. They live in delusional state everything good, wait for one more day and it will stop. But it keeps aggravating till everything fall aparts, other members of family affected. When one child goes wrongway and parents are reluctant to accept it they kept clinging to them, they never settle upon line's crossed now it should stop as they can't hurt their child, they can't give up on them, ultimately that child starts feeling invincible whatever they may do they won't be stopped or punished by parents, and eventually parents unknowingly destroying life of their other child, other members of family, for their love of one bad element that they can't give up. Thats my personal experience, having my life destroyed, good happy smiling family teared apart, because one of sibling gone wrong way started abusing our parents, and they did'nt drew lines, kept forgiving.