Short answer. Yes. If the subscribing witnesses are dead, insane, or none of them resides in the Philippines, the court may admit the testimony of other witnesses to prove the testator's sanity and the will's due execution, and may accept proof of the handwriting of the testator and the witnesses instead.
What the law says
If it appears at the time fixed for the hearing that the subscribing witnesses are dead or insane, or that none of them resides in the Philippines, the court may admit the testimony of other witnesses to prove the sanity of the testator, and the due execution of the will; and as evidence of the execution of the will, it may admit proof of the handwriting of the testator and of the subscribing witnesses, or of any of them.
Rule 76, Section 8 — Proof when witnesses dead or insane or do not reside in the Philippines. Read the full provision →
The rule anticipates witnesses being unavailable
Probate does not collapse simply because the original witnesses cannot testify. The rule applies if it appears at the time fixed for the hearing that the subscribing witnesses are dead or insane, or that none of them resides in the Philippines — covering exactly the situation of witnesses who have since died or moved abroad, leaving none available to appear before the court in person.
Other witnesses can prove sanity and due execution
In that situation, the court may admit the testimony of other witnesses to prove the sanity of the testator, and the due execution of the will. The proof does not have to come from the original subscribing witnesses themselves — anyone with relevant knowledge of the testator's mental state or of how the will was actually executed can be presented instead to establish those same essential facts before the court.
Handwriting evidence is a further available option
The rule also allows the court to admit proof of the handwriting of the testator and of the subscribing witnesses, or of any of them as evidence of the will's execution. This gives the proponent an additional route where testimony alone is difficult to obtain — comparing the signatures on the will against known samples of the testator's and witnesses' actual handwriting from other documents.
Why this matters for heirs facing an unavailable witness
Heirs should not assume a will is unprobatable just because time or distance has taken the original witnesses out of reach. This rule exists precisely so that the death or relocation of every subscribing witness does not permanently block a genuine will from being proved, so long as sanity and due execution can be established through the other means the rule allows, gathered and presented properly well before the hearing date itself.