Introduction

In the Philippines, questions surrounding the transfer or mortgaging of a parent's property by one child, particularly without the consent of siblings, arise frequently in family disputes, estate planning, and real estate transactions. This issue intersects with principles of property ownership, family relations, agency, inheritance, and co-ownership under the Civil Code of the Philippines (Republic Act No. 386), as amended, and related laws such as the Family Code (Executive Order No. 209) and the Property Registration Decree (Presidential Decree No. 1529). The core inquiry is whether a single child has the legal authority to dispose of or encumber a property titled in the parent's name or inherited from the parent, bypassing the involvement of other siblings.

This article explores all relevant legal dimensions, including scenarios where the parent is alive versus deceased, the role of powers of attorney, guardianship, inheritance rules, co-ownership implications, and potential remedies or liabilities. It draws from established jurisprudence from the Supreme Court of the Philippines and statutory provisions to provide a thorough understanding. Key takeaways include the general prohibition on unilateral actions by one child without proper authorization or consensus, emphasizing the protection of familial and property rights.

Legal Framework Governing Property Rights in the Philippines

Ownership and Disposition of Property

Under Article 428 of the Civil Code, the owner has the right to enjoy and dispose of their property without limitations other than those established by law. This means a parent, as the absolute owner, retains full control over their property during their lifetime. A child cannot unilaterally transfer (e.g., sell, donate) or mortgage (encumber) such property unless expressly authorized by the parent or by operation of law.

Absolute Ownership: If the property is registered solely in the parent's name via a Torrens title under PD 1529, only the parent or their duly authorized representative can execute deeds of sale, mortgage, or transfer. Unauthorized acts by a child would be void ab initio (from the beginning) as per Article 1317 of the Civil Code, which states that no one may contract in the name of another without being authorized or having legal representation.
Family Code Provisions: Article 209 of the Family Code reinforces parental authority over the property of minor children but does not extend to children disposing of parental property. For adult children, no inherent authority exists unless through specific legal mechanisms.

Agency and Authorization

A child may act on behalf of a parent only if granted explicit authority, typically via a Special Power of Attorney (SPA) under Article 1878 of the Civil Code. An SPA is required for acts like selling or mortgaging real property and must be notarized and, if executed abroad, consularized.

Without SPA: Absent this, a child's attempt to transfer or mortgage the property is invalid. For instance, in the case of Spouses Lim v. Court of Appeals (G.R. No. 124715, 2000), the Supreme Court held that unauthorized sales by agents are unenforceable.
General Power of Attorney (GPA): A GPA may suffice for administration but not for alienation or encumbrance of real property, which requires specificity to avoid fraud (Article 1878).

If the parent is incapacitated (e.g., due to dementia), a court-appointed guardian under Rule 93 of the Rules of Court may be necessary. Siblings could contest if one child assumes this role without court approval, potentially leading to guardianship proceedings.

Scenarios Where the Parent is Alive

Unilateral Action by One Child

Generally, no. A child lacks inherent authority to transfer or mortgage a living parent's property without consent from the parent, let alone siblings. Sibling consent is irrelevant here because the power stems from the parent-owner, not co-heirs.

Exception: Judicial Authorization: If the parent is a minor or incompetent, a guardian (possibly a child) may seek court approval for disposition under Article 234 of the Family Code (for minors) or Rule 97 of the Rules of Court (for incompetents). However, other siblings, as interested parties, may intervene, and the court ensures the action benefits the ward. Unilateral action without court order is void.
Fraudulent Scenarios: If a child forges documents or misrepresents authority, this constitutes estafa under Article 315 of the Revised Penal Code or falsification under Article 171, punishable by imprisonment. Buyers or mortgagees in good faith may still acquire rights under the "innocent purchaser for value" doctrine (Article 1544, Civil Code), but the child faces civil liability for damages.

Role of Sibling Consent

Sibling consent is not required if the parent authorizes one child exclusively via SPA. However, if the property is conjugal or community property (under Article 116 of the Family Code), both parents' consent is needed, but siblings remain outsiders. Disputes may arise if siblings allege undue influence or simulation of contracts (Article 1345, Civil Code), leading to annulment actions.

Scenarios Where the Parent is Deceased: Inheritance and Co-Ownership

Compulsory Succession and Legitime

Upon the parent's death, property passes to heirs via intestate succession (Articles 960-1014, Civil Code) if no will exists. Children are compulsory heirs entitled to legitime (half of the estate, Article 886). The estate remains undivided until partition.

Co-Ownership: Heirs become co-owners of the property (Article 1078). Under Article 493, no co-owner can dispose of the entire property without consent of all others. Thus, one child cannot transfer or mortgage the whole property without sibling consent; such acts affect only their undivided share.
Jurisprudence: In Heirs of Dela Cruz v. Heirs of Cruz (G.R. No. 162890, 2005), the Supreme Court ruled that sales by one heir of the entire inherited property without co-heirs' consent are valid only as to the seller's share, rendering the transaction partially void.

Partition of Estate

To enable unilateral disposition, partition is required via extrajudicial settlement (if no debts/will) under Section 1, Rule 74 of the Rules of Court or judicial partition (Rule 69). Post-partition, each heir owns their portion absolutely and can transfer or mortgage it without sibling consent.

Extrajudicial Settlement: Requires unanimous agreement among heirs, published for three weeks. If one sibling objects, it shifts to judicial proceedings.
Without Partition: Attempting to mortgage undivided property requires all heirs' consent. Banks or lenders typically demand proof of full ownership or co-owners' concurrence to avoid reconveyance actions.

Advances and Collation

If one child received advances on inheritance (Article 1061), these are collated during partition, affecting shares. However, this does not grant unilateral disposition rights pre-partition.

Testate Succession

If the parent leaves a will (Articles 783-839), a child named as sole devisee for the property can dispose of it post-probate without sibling consent, provided legitime of others is respected. Contesting siblings may file for annulment if the will is invalid (e.g., undue influence, Article 839).

Mortgage-Specific Considerations

Mortgaging follows similar rules but involves encumbrance rather than transfer.

Real Estate Mortgage Law (Act No. 3135): A mortgage requires the mortgagor's ownership or authority. For parental property, only the parent or authorized agent can execute it.
In Inherited Property: One heir can mortgage their undivided interest (Article 493), but lenders rarely accept this due to risks in foreclosure. Full consent is needed for the entire property.
Pactum Commissorium: Automatic appropriation in default is void (Article 2088), but this is tangential.

Remedies and Liabilities

For Aggrieved Siblings

Annulment or Rescission: Under Articles 1390-1402, Civil Code, for voidable contracts due to lack of consent.
Reconveyance: Action to recover property sold without authority (e.g., Naval v. Court of Appeals, G.R. No. 167760, 2006).
Damages: Civil claims against the erring child.
Criminal Actions: For forgery or estafa.

For Third Parties

Bona fide purchasers/mortgagees may retain rights if the title appeared clean (PD 1529), but heirs can sue for annulment within four years (Article 1391).

Prescription

Actions for annulment prescribe in four years; reconveyance based on trust does not prescribe against a trustee (Article 1456).

Special Cases

Adopted or Illegitimate Children

Under Republic Act No. 8552 (Adoption) and Article 176 of the Family Code (as amended by RA 9255), they have equal rights, requiring their consent in co-ownership scenarios.

Properties Under Agrarian Reform

CARP-covered lands (RA 6657) have additional restrictions; heirs must comply with DAR rules, often requiring collective consent.

Corporate-Owned Properties

If the parent owns via a corporation, stock transfer rules apply (Corporation Code, Batas Pambansa Blg. 68), not directly sibling consent.

Conclusion

In summary, under Philippine law, a child cannot generally transfer or mortgage a parent's property without the parent's authorization if alive, or without sibling consent if deceased and the property is co-owned. Exceptions exist through legal instruments like SPAs, court orders, or post-partition ownership. These rules safeguard against familial discord and fraud, promoting equitable distribution. Parties should consult a lawyer for case-specific advice, as jurisprudence evolves, and seek notarial or judicial validation for transactions to avoid costly litigation. Understanding these principles is crucial for estate planning to prevent disputes among heirs.