Is it permissible to accept a person's declaration that he is a brother of the deceased from the father, and for a financial right to be based on it, knowing that there is conclusive evidence of the falsity of this declaration, and that the wording of the declaration is: "We, the undersigned, bear witness that so-and-so is a brother of the deceased so-and-so from the father, and thereupon we sign"?

Your acknowledgment that the aforementioned person is the paternal brother of your deceased cousin makes him more entitled to inherit from him than you. This acknowledgment is binding and enforceable against you if you made it while you were of sound mind and full awareness, because a person's acknowledgment against himself is the strongest of proofs. This acknowledgment is enforceable against you. However, if there is another heir to the deceased besides you who has not acknowledged as you have, then your acknowledgment is not binding on him, and it is considered, in his regard, testimony that becomes void upon retraction before judgment.