Talk to the Philadelphia Defender's Association. You will have to provide proof of his lack of ability to pay for a lawyer. Call them today, to give them as much time as possible to both take him on as a client, and meet with him before his hearing date.
If he is incarcerated and cannot afford a private lawyer, he will be appointed one and you will not need to be involved. If he is on the street, he should call them at 215-568-3190.
If you qualify financially often you apply through the PD's office prior to first appearance & in some state it is done on the say of arraignment (prior to entering a plea). Contact a local PA criminal attorney for advice - many do not charge a fee for an initial consultation. I am a California attorney not licensed in PA and not familiar with their laws & procedure. Good luck
This is not intended to be legal advise or as legal representation. I am a California personal injury attorney . Be aware that every state has its own statute of limitations; and statutes & case laws that govern the handling of these matters.
Go to the second floor of the Criminal Justice Center. At the information center tell them you cannot afford a lawyer. They will direct you to the PD who will evaluate whether your babyfather is eligible. If not, consider an attorney who will provide affordable and personal representation. I practice Criminal Defense in Philadelphia. Do not hesitate to contact me if you wish to discuss this matter.