Short answer. Possibly, under the pedigree exception. Section 41 of Rule 130 allows a deceased or unavailable relative's declaration about pedigree into evidence if made before the controversy arose and the relationship itself is shown by evidence other than that statement — so the letters could count, but only alongside independent proof of the tie.

What the law says

The act or declaration of a person deceased or unable to testify, in respect to the pedigree of another person related to him or her by birth

Rule 130, Section 41 — Act or declaration about pedigree. Read the full provision →

Why pedigree needs its own exception

Ordinarily, a statement made outside of court by someone who cannot be cross-examined is hearsay and inadmissible. Facts about family relationships, however, are often known only through statements handed down within a family — letters, remarks made in passing, family records kept informally — precisely because the people who knew a relationship firsthand are frequently dead by the time it needs to be proven. Section 41 carves out room for exactly that kind of evidence, on the theory that a family member speaking about pedigree, with nothing to gain from lying about it, is reasonably trustworthy.

What the statement has to be about

The rule defines pedigree broadly: it includes relationship, family genealogy, birth, marriage, death, the dates when and the places where these facts occurred, and the names of the relatives, and reaches as far as facts of family history intimately connected with pedigree. A letter calling someone "my son," noting a birth date, or describing how family members are related to one another falls squarely within that definition.

Two conditions that cannot be skipped

The exception comes with real limits. First, the declarant has to be deceased or unable to testify — a living relative who could simply take the stand does not get the benefit of this shortcut. Second, and often overlooked, the statement must have been made before the controversy arose, so a letter written specifically to help win a pending inheritance dispute would not qualify the way one written years earlier, with no dispute in sight, would.

Why the letters alone are not enough

The rule explicitly requires that the relationship between the two persons is shown by evidence other than such act or declaration. In other words, the pedigree statement cannot be used to prove its own foundation — something else in the record, such as another witness, a document, or a different family record, has to independently establish that the two people were actually related before the letters can be used to fill in the further details of that relationship.

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.