Short answer. Yes. What matters is that each witness was competent at the moment the will was attested. Article 822 provides that if the witnesses were competent at the time of attesting, their becoming incompetent afterward does not prevent the allowance of the will. A disqualification that arises later does not undo a validly witnessed will.
What the law says
If the witnesses attesting the execution of a will are competent at the time of attesting, their becoming subsequently incompetent shall not prevent the allowance of the will.
Civil Code, Article 822 — Later Incompetency Does Not Matter. Read the full provision →
Competency is tested at the moment of attestation
The law fixes a single point in time for judging a witness's qualification. Article 822 says: If the witnesses attesting the execution of a will are competent at the time of attesting, their becoming subsequently incompetent shall not prevent the allowance of the will. So the question is always whether the witness was competent when the will was signed and attested — not whether he stayed competent forever after. If all three witnesses were qualified at that moment, the will is properly witnessed, and later events cannot reach back and spoil what was already done correctly.
Later disqualification simply does not count
Things can change in a person's life after a will is executed. A witness might, in later years, be convicted of a disqualifying offense, lose mental capacity, or otherwise fall short of what the law requires of a witness. Article 822 makes clear that none of this matters to the will. Because he was competent at attestation, his subsequent incompetency shall not prevent the allowance of the will. The will does not have to be re-executed, and it is not weakened, just because a witness's situation deteriorated in the interval before the testator's death.
Why the rule works this way
The point of witnesses is to observe and vouch for the execution of the will as it happens. Once that act is validly witnessed, its integrity is settled. It would be unjust and impractical to let a will fail because, years later and through no fault of the testator, a witness became disqualified. The testator did everything required at the proper time; he cannot control what becomes of his witnesses afterward. Article 822 protects the will's validity against those later, uncontrollable changes, keeping the focus squarely on the conditions that existed at the moment of attestation.
What the rule does not cure
This protection is narrow, and it is worth being clear about its limits. Article 822 saves a will only where the witnesses were genuinely competent at the time of attesting. It does nothing for a will that was defectively witnessed from the start — for instance, if a witness was already disqualified when the will was signed, or if the formal requirements for witnessing were not met. The article rescues wills from later changes in a witness's status; it does not forgive a defect that existed at the very moment of execution. Those go to whether the will was properly made in the first place.