Short answer. Yes, if the buyer acted in good faith. Alienations made by an excluded heir before the judicial order of exclusion are valid as to third persons who acted in good faith. The co-heirs are not left without a remedy — they recover damages from the disqualified heir instead.
What the law says
Alienations of hereditary property, and acts of administration performed by the excluded heir, before the judicial order of exclusion, are valid as to the third persons who acted in good faith
Civil Code, Article 1036 — Acts Done Before the Order of Exclusion. Read the full provision →
The rule protects the buyer, not the heir
It can look as though unworthiness is being rewarded, but the article is not about the heir at all. It is about a stranger who dealt with someone who appeared, on the face of the record, to be an heir entitled to sell. Until a court has said otherwise, that appearance is all a buyer has to go on. Rather than unwinding every transaction touching estate property, the Code lets the completed sale stand and shifts the loss onto the person who caused it.
Good faith is the condition, and the date is the pivot
Two things have to hold. The buyer must have acted in good faith — meaning without notice that the seller's right as an heir was being contested. And the alienation must have come before the judicial order of exclusion. A buyer who knew of a pending unworthiness case, or who bought after the order, is outside the protection. So the practical enquiry is usually documentary: what was on record about the estate, and what the buyer knew, on the date the deed was executed.
The co-heirs' remedy runs against the heir
The article's second half is the balance: but the co-heirs shall have a right to recover damages from the disqualified heir. That is a personal claim for the value lost, not an action to recover the property from the buyer. It is worth being clear-eyed about what that means in practice — the claim is only as good as the disqualified heir's remaining assets, which is why pursuing him promptly, before the proceeds are dissipated, matters far more than it might appear.
Acts of administration are covered too
The protection is not confined to sales. The article extends to acts of administration performed by the excluded heir, so leases granted, repairs contracted, and dealings with tenants or suppliers in the interim are not automatically undone either. If you are in this position, gather the deeds and their dates, the title history, and anything showing what was on record or communicated to the buyer, then take advice on both the exclusion case and the damages claim together.