D..
You say he is highly emotional. I wonder if he is not telling you that he's suicidal. Maybe that's a leap - maybe it's not. Maybe he is afraid to take care of his daughter. Maybe he is depressed and trying to fight his way out of falling into clinical depression.
I think perhaps it would be good for him to go to counseling. Ask him to do it. Ask him if you can help him start the process. He may be so overwrought that he can't do anything but what he's doing now. And he hasn't bottomed out, either.
What this feels like to him is a death in the family, D.. Except she's not dead and she doesn't want him, and she doesn't want her child. It's a double whammy because he doesn't recognize the person she is and he never expected this kind of person to emerge from the person he thought he married. He needs counseling to help him get through it. And he needs a lawyer to explain what happens so that he can mentally prepare. That includes if he loses custody because he gave the baby to the grandmother.