S.B.
Sometimes the best decision is to let go. She isn't ready for this and it appears neither is the father. You can't force this on her. The only one who will suffer in the long wrong is the baby.
There is a home out there for that child who will love him more than anything. That is what parents do. She is not a parent nor is she ready to be a parent. Babies are adaptable and in no time would bond with his new family.
If she wants to put the baby up for adoption, you don't have much to say about that. That might be her way to show how much she loves him.