What is the ruling of Islamic law on a son taking money from his father in exchange for selling three carats of land, knowing that this money is designated for covering the installments of his two sisters' dowries and for construction, and that the mother and sisters considered this amount as part of the son's inheritance to appease them?

Your renunciation of inheritance is void before it is established, for lifespans are in God's hands, and a person's wealth does not transfer to heirs until after their death. What your father paid you is a gift that you are not required to repay. There is no blame in him singling you out with it if there was a legitimate reason, such as need or engagement in knowledge, and the opposition of your mother or siblings holds no weight.