15-year-old falsification of public document case

Hello. I need help regarding falsification of documents. The incident happened 15 years ago when an uncle of mine falsified the signature of my grandfather. Suffice it to say he got the SPA and was able to loan money from the bank using the SPA and the property as collateral, the amount of which was less than 50k. When it was discovered, he borrowed money from their eldest sister, paid off the loan, and gave all papers and documents to her. The problem is that their youngest sister is always using the case to rattle him. They need to pay the estate tax but she wants him to pay all the amount, so she had our uncle summoned by the barangay for falsification charges. She's using it to force my uncle to pay for the estate tax. They should split the estate tax between three people, but the youngest is using the falsification charges against my uncle to make him pay for her share, I think.

I've read here that there is a prescription for falsification and use of public documents (10 years, I think). My question is, can their youngest sister still file falsification charges against him? Can she file a case of falsification against my uncle when it was my grandfather's signature he forged? My grandfather is long dead, by the way; he died the same year, but before the falsification incident. Also, what can we do to make her stop?

To my knowledge, there are no barangay and fiscal complaints filed at that time, nor are there any police blotters when it happened. She's only started using the case against my uncle five years later, when the estate tax payables were piling up.

My mother, the eldest sibling he borrowed money from to pay off the loan, doesn't want to press any charges against him, but she's already suffering from the stress and tension between her two younger siblings. He always borrows money from my mother for these things, and it's already causing her blood pressure problems. We want to avoid aggravating her medical condition.

Thank you in advance.

It has been been 15 years so its over! statue of limitation only up to 10 years.

Thank you very much. Is there something we can do though or advice my uncle to make her stop using the case against him? It's becoming too much of a headache on us all whenever the falsification issue is brought up, especially since she keeps involving the barangay, pressuring my mother to file charges against him, and threatening to file the case at the fiscal's office.

Relax! Let her waste her time as it will not prosper!