A father and son have the same name the father is deceased the son signs?

If he is not the owner of the property he is committing a fraudulent act. He is acting to deceive the other party. He would be forging his father's name and concealing the fact of his death. In fact, he would be creating a cloud on the title to the property that would be quite easy to detect and expensive to fix. If he uses the deception to obtain money, think very serious criminal charges.