I'd say the others are correct. Most states are very aggressive about collecting child support for mothers on state assistance. They'll go after whoever the mother names and it's up to him to prove that he's not the father. I'm not a lawyer but I've spent time in family court and I believe that even if not the bio father, if they were married or he was common-law husband, they may still require him to pay support. He needs a lawyer.
My ex lost her job and went to DHS claiming three children living with her and me as the father, even though my two lived with me and the third I'd never even seen. She told me she'd let it be assumed that all three were mine because she was afraid of both of the possible candidates for the actual paternity of the the other baby. I told her I was going to get my lawyer to throw the book at her; she withdrew her first app., submitted another for just the third child. Don't know who she named on the new app.