Legal Question in Family Law in California

If the father resides at the house with his parents, substituted service may work. If the father does not live there, leaving papers at his parent's home will not work.

Ms. Kock is correct. If that is his residence, then you can have him served there by "substituted service." If that is not his residence, however, and you can't find him, you will have to petition the court to serve him by newspaper publication.