It is prescribed for
a Muslim to slaughter an Ud-hiyah on behalf of himself and his living and dead family members. Moreover, there is nothing wrong with offering more than one Ud-hiyah and it is recommendable to eat from it and give the poor from it. It is noted that the needy are many but one should search for them. As for what you mentioned about your grandfather's bequest, you should consult the legal court to consider it.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.