IF the baby had been BORN, it is possible that the MINOR boyfriend could be held accountable for the birthing expenses. However, since the baby was NOT born, that does not matter. In addition, if the baby had been BORN, per Ohio law, it is possible that the boyfriend's PARENTS could have been liable for the birthing expenses. Under Ohio child support law.
However, since the baby was NOT born, then OP would have to prove that a contract existed. I do not see a contract based upon what OP stated. There may have been a promise by the boyfriend's parents, but what was the consideration?