The "dad" you are talking about is nothing else but a younger version of a titanus gojira specie, called dagon, and Godzilla already existed when dagon was still alive
When kong found his family in hollow earth he didnt feel alone being the last ape anymore But we didnt see another godzilla in through the millenium era since they didnt leak where minilla went And godzilla junior died so godzilla is last of his kind but he still acts normal and cranky when effected by other titans 😢
