Short answer. It depends on his domicile. Article 829 of the Civil Code provides that a revocation made abroad by a person not domiciled in the Philippines is valid if it follows either the law of the place where the will was made or the law of his domicile at the time of revocation.
What the law says
A revocation done outside the Philippines, by a person who does not have his domicile in this country, is valid when it is done according to the law of the place where the will was made, or according to the law of the place in which the testator had his domicile at the time; and if the revocation takes place in this country, when it is in accordance with the provisions of this Code.
Civil Code, Article 829 — Revocation Made Abroad. Read the full provision →
The rule for revocation outside the Philippines
Article 829 of the Civil Code provides a specific rule for revocations made abroad by persons who are not domiciled in the Philippines: A revocation done outside the Philippines, by a person who does not have his domicile in this country, is valid when it is done according to the law of the place where the will was made, or according to the law of the place in which the testator had his domicile at the time. If your father was domiciled in the United States at the time he revoked his Philippine will, the revocation does not have to follow Philippine law. It is valid if it complies with either the law of the state where the original will was made or the law of his domicile at the time of revocation.
Two laws that can validate the revocation
Article 829 offers two alternative governing laws when a non-domiciliary revokes a will outside the Philippines. The first is the law of the place where the will was made. If the Philippine will was executed in the Philippines, then Philippine law is one option for evaluating the revocation's validity. The second is the law of the testator's domicile at the time of revocation. If your father was domiciled in a particular state when he revoked, that state's law also applies. The revocation is valid if it satisfies either of these two laws — compliance with one is sufficient. A revocation that meets the requirements of the domicile state does not need to additionally comply with Philippine law to be recognized.
The domicile question is critical
Whether your father was domiciled in the Philippines or in the United States at the time of revocation determines which legal framework applies. Article 829 specifically covers the case of a person who does not have his domicile in this country. If he had abandoned his Philippine domicile and established a new domicile in the United States, he falls within the article's coverage — and the law of either the place where the will was made or his domicile governs the revocation. If, on the other hand, he never abandoned his Philippine domicile and was merely residing abroad temporarily, the picture may be different and Philippine law may carry more weight.
Revocation that takes place in the Philippines
For completeness, Article 829 also addresses the reverse situation: when revocation takes place in the Philippines. In that case, it must comply with the provisions of the Civil Code regardless of the testator's domicile or where the will was made. The choice-of-law flexibility applies only to revocations made abroad. When the act of revocation — the burning, cancellation, tearing, or execution of a new will — happens on Philippine soil, Philippine law governs exclusively. This makes Article 829 specifically relevant to situations like your father's, where the revocation was done while physically outside the Philippines.