Teddysgirl ... please allow me to share with you a little based on a very recent experience.
My daughter has a son with a man who is a drug addict. They were engaged but broke it off at the end of last year. When she was just a few months pregnant she started to notice things that made her question if he had a drug problem. I will spare you the details of this very long story, BUT currently he is awaiting sentencing on several drug charges.
I don't know what state you live in but in our state, since they were never married, she has full custody of her son and even though the father signed an "Acknowledgement of Paternity" and is on the birth certificate, he has no "rights" until he petitions the court for them. Which, he hasn't. As a result of him not petitioning the court to invoke his rights, his refusal to respond to a summons for a hearing on child support, and the fact that his whereabouts are unknown ... my daughter is in the process of a Single Parent Adoption. She will be adopting her own son, thus terminating any future rights of the father.
I suggest you retain a lawyer and discuss these possibilities. It seems harsh, but in our case, I honestly think the "father" will be more relieved that he's off the hook.