Is this a void marriage? Change of age (year of birth) to pursue the marriage

Hi good day.

Its my first time to post here. I would like to ask if this is a void marriage?
Scenario:
My boyfriend was married in September 1994, he was 19 years old and his ex wife was 17 that time. ex-wife was born on july _, 1977. She was already pregnant to pursue their wedding, to be at legal age to marry they changed the year of birth (from
1977 to 1976) in the marriage license and marriage contract.


They got separted after 5years. They been separated for 18 years now with no communication. Their daughter is at legal age now and already have her own family. Ex-wife already have her own family with 1 child to other man.
My boyfriend and I were going to have a child soon. And we are planning to get married. But their marriage is registered at NSO.
What will be the process to declare that his previous marriage is a void marriage?

Hoping for your response and legal advice regarding this matter.

Thank you.

seek a lawyer since only the court can declare a marriage void.

1. Obtain a copy of the wife's birth certificate with the NSO.

2. HIRE A LAWYER AND FILE A PETITION FOR DECLARATION OF NULLITY based on Minority.

Especially for purposes of remarriage, your partner has to obtain a decree of nullity first.