adoption

My husband is trying to adopt my son and we not able to locate the biological father because i don't know his last name, last known address, where is parents live and a phone number and the courts say i need to send a cerified letter to him and i don't know where to locate him what can i do know.

You only need to put the notification in a newspaper of last known where abouts. This gives the perseption that you all have tried to get in touch even though mr. invisible has not kept in contact or made the effort to try to get custody.
If you can afford to run a couple of notices in a couple of newspapers then it should cover the notification. But you need to schedule the adoption and post the date of the hearing. I would give it 90 days and proceed to adopt and have a happy life.
Congradualtions on the adoption.