Short answer. Yes. Where an illegitimate child dies leaving a surviving spouse and his parents, the Civil Code reserves one-fourth of the estate for the parents and one-fourth for the widow or widower. The remaining half is free portion, which the deceased could dispose of by will as he wished.
What the law says
If only the widow or widower survives with parents of the illegitimate child, the legitime of the parents is one-fourth of the hereditary estate of the child, and that of the surviving spouse also one-fourth of the estate.
Civil Code, Article 903 — Legitime of the Parents. Read the full provision →
The parents' share moves with who else survives
The article states three situations and the parents' share is different in each. If the illegitimate child leaves neither legitimate descendants, nor a surviving spouse, nor illegitimate children, the parents' legitime is one-half of the estate. If the child leaves children of his own, whether legitimate or illegitimate, the parents are not entitled to any legitime whatsoever — they are excluded completely by the deceased's own children. It is only in the middle case, where a widow or widower survives together with the parents and there are no children, that the quarter-and-quarter split applies. Grandchildren of the deceased count as descendants and produce the same exclusion.
How this article reads today
These fractions were framed on the classification of children used when the Civil Code took effect in 1950, and the article must be read subject to the Family Code. The Family Code provides that the legitime of each illegitimate child is one-half of the legitime of a legitimate child, and that "except for this modification, all other provisions in the Civil Code governing successional rights shall remain in force." The Family Code also recognises a single class of illegitimate child, so the old Civil Code sub-classifications no longer sort heirs into tiers. What survives is the structure of this article: parents and spouse taking a quarter each when they survive together and no descendants exist.
Legitime is a floor, not the whole answer
A legitime is the minimum the law reserves; it is not necessarily all an heir receives. Where the deceased left a will, the parents and the spouse cannot be given less than their reserved quarters, and a will that impairs a legitime can be reduced to the extent of the impairment. Where there is no will at all, the estate is distributed by the rules of intestate succession rather than by this article, and the resulting shares may differ. Debts, funeral expenses and taxes are settled before any share is computed, so a quarter of a heavily indebted estate can be worth very little. Filiation to the parent claiming must also be proved.
What a parent in this position should do
Do not sign a deed of extrajudicial settlement, a waiver or a quitclaim before the shares have been worked out. Once signed, these documents are difficult to undo. Collect the birth certificate and any record of acknowledgment establishing your filiation to your son, his marriage certificate, his death certificate, and a full inventory of what he owned and owed at death. Establish whether he left any child, because a single surviving child removes the parents' legitime entirely. Estate tax deadlines run from the date of death regardless of any family dispute. If the widow disputes your share, book a consultation before the estate is distributed.