He will get the baby back. The marriage contract trumps all bonds and the family would be fools to fight it.
Happended to a friend who adopted, years and years ago. Sad crazy women.
He told her we had moved away and he lost track of us. this was 40 years ago and she made no attempt to find us. He didn't tell me for several years and I was thankful that I didn't know because I would have been worried that she would show up on our doorstep one day. This was back in the day before open adoptions.