marriage certificate not registered eversince for more than 20 years

i got my mom and dad separated for more than 5 years now, but later po we just found out na although kinasal sila hindi pla nkaregister ung marriage certificate nila eversince, is the marriage null and void due to this?, does it mean na hindi cla legally married meaning na pwede ulit cla mgpakasal without getting annuled? and if ever my mom is using my fathers surname does he got the right pra maghabol sa properties like the house which is under my mothers name?, and other staff like pension and benefits na nkukuha ng mom ko? i'll stay online because i need a quick reply on this please..

please answer my query.. i seriously need an advice on how to deal on this..please..

registration of marriage is required, but it is not an element that affects the validity of the marriage. it makes the solemnizing officer liable, but the marriage is still valid.

the remedy is to file the marriage certificate with the civil registrar.