Validity of last will of a mentally ill testator


Persida Acosta

Dear PAO,
Can we disregard the last will of our grandmother because she was already out of her mind when she died? One of my cousins is disputing the contents of the last will of our grandmother because it was unfavorable to him. He is alleging that her last will is of no value because she was already mentally deranged at the time of her death. Some of our other relatives are saying, however, that our grandmother made her last will years before she went insane. Can you advise us if her last will is still valid because of her mental status? Thank you!

Dear Ronnie,
The law provides for the qualification of a person who executes a last will and testament for his estate. According to Article 798 of the New Civil Code of the Philippines, it is necessary that a testator should be of a sound mind at the time of his execution of a will.

“Article 798. In order to make a will, it is essential that the testator be of sound mind at the time of its execution.”

This cited provision emphasizes that the qualification of having a sound mind should be present at the time of the execution of the will, not after its execution. Because of this, a change in the testator’s mental health after the execution of a will does not affect and invalidate the last will if the testator was of sound mind when he executed it. This is expressly mentioned in another provision of the Civil Code that states:

“Article 801. Supervening incapacity does not invalidate an effective will, nor is the will of an incapable validated by the supervening of capacity.” (Ibid)

Considering this, the mere deterioration of your grandmother’s mental health prior to her death, as a supervening incapacity, does not invalidate her last wilI. Her qualification as a testator is determined at the time of the execution of her will, not after. Furthermore, it is important to note that:

“Article 80. The law presumes that every person is of sound mind, in the absence of proof to the contrary.

The burden of proof that the testator was not of sound mind at the time of making his dispositions is on the person who opposes the probate of the will; but if the testator, one month, or less, before making his will was publicly known to be insane, the person who maintains the validity of the will must prove that the testator made it during a lucid interval.” (Ibid.)

Thus, should your cousin still insist that the last will of your grandmother is defective because of her mental condition, it will be up to him to prove his claim since the law gives a presumption of sound mind to testators and puts the burden to prove otherwise to the person who opposes it during the probate proceedings.

Again, we find it necessary to mention that this opinion is solely based on the facts you have narrated and our appreciation of the same. The opinion may vary when the facts are changed or elaborated.

We hope that we were able to enlighten you on the matter.

Editor’s note: Dear PAO is a daily column of the Public Attorney’s Office. Questions for Chief Acosta may be sent to


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