Does the old man need a gift to erect a monument?

This varies with local customs. As far as my family is concerned, a monument stands in my uncle's grave. If you invite my nephew to attend, just buy some paper money and burn it, not with the gift.

According to folk custom, a monument can be erected before Tomb-Sweeping Day or during the Great Cold Festival, and at some time after the deceased is buried. On this day, after the monument was built, the children or main relatives of the deceased prepared some meals at home, and some invited monks to bring paper money to the tombstone in front of the grave to provide meals, burn paper and kowtow, and the monks prayed. After the ceremony, go home and have dinner together. The expenses are borne by the children, and relatives don't have to give gifts.