When it starts that the elder kids stop treating the younger ones with affection and the younger ones become disobedient to the elder ones then to treat this recite 100 times
اِنَھُمْ یَکِیدُوْنَ کَیْدَاً ۙ وَّ اَ کِیْدُ کَیْدًا
and blow on the pillows of the children. Be careful that the pillow of one must not be used by the other one. This is to be practiced for forty days.