Should the house be returned to the uncle who reproaches with the money he generously gave to buy the house?

If your uncle gave you the money as a gift and a donation, it became your property upon taking possession. He does not have the right to revoke his gift, due to the Prophet, peace and blessings be upon him, saying: "It is not permissible for anyone to give a gift and then take it back, except for a father regarding what he gives his child," and his saying: "The one who takes back his gift is like a dog that vomits and then returns to its vomit." The house you bought with the money is yours. You must be keen to maintain ties with your uncle, and if you give him some money in return for his kindness, that is better.