Is it permissible to supplicate for the destruction of my grandfather due to his extreme injustice towards my parents and his failure to fulfill his promise to them?

It is not permissible to supplicate for the grandfather's destruction or similar outcomes, even if he has wronged your father and oppressed him. The grandfather has a right to dutifulness just like the father. Ibn Hazm stated that showing dutifulness to parents and grandparents is an obligation. If the grandfather commits wrongdoing, he can be gently enjoined to good and forbidden from evil, and supplicated for guidance. Oppression is forbidden for everyone, and its prohibition is particularly emphasized when it concerns relatives.