Short answer. By the intestate rules. Legal succession takes place only as to the property the will did not dispose of, so the estate is settled under two regimes at once: the will governs what it covers, and the law governs the remainder among the legal heirs.

What the law says

When the will does not institute an heir to, or dispose of all the property belonging to the testator. In such case, legal succession shall take place only with respect to the property of which the testator has not disposed

Civil Code, Article 960 — When Intestate Succession Applies. Read the full provision →

What the law says

The testator cannot deprive his compulsory heirs of their legitime, except in cases expressly specified by law.

Civil Code, Article 904 — The Legitime Cannot Be Taken Away. Read the full provision →

Two regimes, running side by side

Article 960 lists partial disposition as a trigger for intestacy: legal succession takes place When the will does not institute an heir to, or dispose of all the property belonging to the testator. In such case, legal succession shall take place only with respect to the property of which the testator has not disposed. Nothing about the will is defective — Article 841 expressly validates a will that does not cover the whole estate. The settlement simply has two halves, and confusion comes from treating it as one: the properties the will names are distributed as it directs, and everything else as though there were no will at all.

Identifying 'the rest' is the real work

The residue is not a figure in the will; it is the difference between what your father actually owned at death and what the will disposed of. So the first task is an honest inventory of the estate, and Article 1078 sets the order of operations by holding the whole estate in common among the heirs before partition, subject to the payment of the debts of the deceased. Where he was married, the couple's property regime is liquidated first, so that only his own share enters the estate. Assets people overlook — a lot registered in one name only, an unregistered vehicle, receivables — belong in that inventory.

Who takes the remainder

Article 961 vests the inheritance, in default of testamentary heirs, in the legitimate and illegitimate relatives of the deceased, in the surviving spouse, and in the State. Which of them take, and in what proportion, depends on who survived your father. One point runs across both halves of the settlement: Article 904 provides that The testator cannot deprive his compulsory heirs of their legitime, except in cases expressly specified by law. — so the legitime is tested against the estate as a whole, not against the leftover.

The trap of being an heir twice over

In a partly testate estate the same child is often both a testamentary heir, as to what the will gives him, and an intestate heir as to the rest. Article 1055 governs what happens if he wants out: If a person, who is called to the same inheritance as an heir by will and ab intestato, repudiates the inheritance in his capacity as a testamentary heir, he is understood to have repudiated it in both capacities. The reverse is gentler: someone who repudiates as an intestate heir without knowing he was also named in a will may still accept in that capacity. Read the will before renouncing anything: order and knowledge both matter.

Cases citing this provision

These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.

Related provisions

Note. Statute text quoted on this page is reproduced from the official enactment and is linked to the full provision. The explanation around it is general legal information from Vivas & Nobles Law Office, not legal advice. Whether it applies to your situation depends on facts only a lawyer reviewing them can assess.