If a man dies while having a dispute with another, what must the opponent do to end this dispute and ensure the validity of his Hajj?

Enmity does not affect the validity of Hajj, but striving for reconciliation is obligatory, because a Muslim abandoning his brother is only permissible with a legitimate Islamic justification. Whoever has been wronged or has animosity with his brother, must seek his forgiveness, or return his right to him, or pardon him. The noble Hadith states: "The gates of Paradise are opened on Mondays and Thursdays. Then every servant who does not associate anything with Allah is forgiven, except for a man between whom and his brother there is enmity. It will be said: Wait for these two until they reconcile."

If the adversary is deceased: if he was an oppressor, the living person should forgive him. If he was wronged financially, the money should be returned to his heirs or given as charity. If he was wronged in his honor, one should supplicate for him and seek forgiveness for him if he was a Muslim. However, if he was a disbeliever, giving charity with the intention of absolving the right of another is permissible, but supplicating for him or seeking forgiveness for him is not.