Adopting Stepson in Pennsylvania

My husband wants to adopt my son. He has raised him for the last 4 1/2 years and there has been no contact from the birth father in almost 6 years. Unfortunately we are paying off $6000 to the divorce/custody lawyer and were really hoping we could file the paperwork on our own. Has anyone done this before and if so...where do I start!?!?!? We want to file paperwork to terminate his rights and to file for the adoption. I don't think he would voluntarily sign away his right b/c he will look horrible to his father but I read that we can have his rights terminated b/c of the amount of time he has had no contact. I so look forward to anyone advice or personal experiences.