A will is a unilateral legal act, that is, a will is a legal act that can produce expected legal consequences based on the testator's unilateral expression of will. The will made by the old man is valid. The testator must have full capacity for civil conduct, and those with limited capacity and those without capacity for civil conduct cannot make a will without capacity for will.

Article 134 of the Civil Code of People's Republic of China (PRC) * * * A self-written will is written and signed by the testator, indicating the year, month and day. Article 135 A will written by an agent shall be witnessed by two or more witnesses, one of whom shall write on behalf of the testator, agent and other witnesses, and shall be signed by the testator, agent and other witnesses, indicating the year, month and day. Article 136 A printed will shall be witnessed by two or more witnesses. The testator and the witness shall sign on each page of the will and indicate the year, month and day.