A:
the man whose father died while being displeased with him should repent to Allah (Glorified and Exalted be He) and seek His Forgiveness for being undutiful to his father. He should be dutiful to his father after his death by praying for him and asking Allah's Forgiveness for him. He should give charity on his behalf. He should be kind to his paternal relatives and his father's friends. If his father left a will, he should carry it out.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.