Googled: Child support, Paternal rights, unwed fathers, custody and all combinations there of.
The main character, Mike, dated and slept with a woman, Trish. They broke up just before she found out that she was pregnant. For reasons of her own, she never told him about their son. Then, when the child was five or six, she's killed in an accident.
Her parents (maybe just her mother) try to take care of the boy but they are elderly and money is very tight.
I'm assuming that if they apply for assistance, Children and Family Services is going to ask about Mike and where he's been.
If Grandma can provide them with a name and an employer, NYPD, they will find Dad.
Do they haul him into court or just send him a bill for child
If Grandma is really not capable of caring for a kindergartner, either of medical or financial reasons, will they take the boy into foster care (and send Mike a bill) or call him and say, come get your kid?
If he wants the child, what hoops does he have to go through to establish paternity? His name is on the birth certificate, the Grandmother can swear that the mother named Mike as the father and he's doesn't doubt that he is.
I found a site that talks about unwed father's and their adoption rights, but it assumes that the fathers were aware of the baby either before or soon after the birth.
edited for spelling