Druthirashtra suffering for his own feeling of inadequacy as king nourishes the ego and vanity of his son. Veda Vyasa had warned the parents yet they chose the harakiri mode, playing the victim card went about abetting their son in his schemes and wrong doings.
Drona incited by the inability to feed his son seeks the refuge of his friend Drupada who humiliates him...Drona then swerves from the code of ethics of a Brahmana...picks arms and by being involved in the killing of Abhimanyu in the most unethical of ways and because of his inability to rein in his son paves way for his own destruction.