Is it permissible for a widow to slaughter an Udhiyah (sacrificial animal) with the intention of reviving the Sunnah of the Messenger of Allah (peace and blessings be upon him) and as a charity on behalf of her deceased husband, knowing that the funds for the Udhiyah are from the inheritance of the deceased husband?

The fatwa issued states that it is permissible to offer a sacrifice on behalf of the deceased. Therefore, there is no objection to the widow sacrificing on behalf of her deceased husband, whether using what she inherited from his wealth or other means. The reward for this will reach him, and she will be rewarded for reviving the Sunnah and for her righteousness and kindness towards her deceased husband.