Is it grounds for annulment?

Hello,
I have been reading most of the articles on null/void marriages and getting some ideas that help me read further. I would appreciate your input/advice.
This involves my father.
My mother died in May 2002. He remarried in December 2004 to a widow as well.
My father is aware that his marriage took place in Manila. However upon inquiry, there is no record of the said marriage in Manila. It is registered in San Juan City instead.
Checking further, it is written on the status part of the marriage certificate of my father that he is single (instead of widowed).
is this grounds for fraud to as stated in article 85, 4 and 86, 1.
As a presumption, given that there is no marriage license, is this null from the beginning? (ab initio)

Thanking you in advance

Looking forward to some input or referral to some good lawyers around.

If there is someone to be concerned about the validity or nullity of 2nd marriage upon death of the first, then it would not be you. The second marriage is valid afaik whether your father was single or widowed at that time . They were married legally until court declares not to be so.

If someone is to file nullity of marriage, it should not be you in other words.