What can I offer my deceased husband other than charity, prayers for mercy upon him, and taking care of our children?

The best things that can be offered to the deceased are charity (sadaqah) and supplication (du'a). The reward for both reaches the deceased by consensus, and the reports regarding this are well-established. Among the virtuous deeds as well are performing Hajj and Umrah on their behalf, especially if these were obligatory upon them and they did not fulfill them; in such a case, they must be performed from their estate. Ongoing charities (sadaqat jariyah) are diverse, such as building mosques, digging wells, and endowing copies of the Qur'an and books of knowledge. The avenues for spending money and dedicating its reward to the deceased cannot be limited.