My son has not seen his “natural father” since he was around 18 months old, he is now about to turn 7 years old. I've been with my husband since he was about 24 months old, if not longer, and my son only knows him (my husband) as his father. We are currently attempting to do a Name Change.

Questions:
:: What will stand in court as proof that we've exhausted all avenues to locating the “natural father”?
:: Can we file for abandonment? If so, how?
::

Key facts in our case:
:: Knows my husband as his Dad
:: Live in California
:: Have a standing RO (Restraining Order)
:: Unable to locate him through his last known address and mother (sends letters back as “return to sender, doesn't live here”)
:: Hired a PI who was unable to locate him