Male Pionus Maximillion keeping hen from baby

Max our Maximillion parrot will not let Milly look after their baby. Milly laid 5 eggs and sat on them for a month.One hatched the other eggs were not fertilized so we took them out. The remaining baby is 2 weeks old and Max will not let Milly into the nesting box to feed it or to look after it. She has left it alone at night.

When the eggs were in the box she was fine Max fed her and she fed the baby. Now Max won't let her near it and it is being left alone at night. Max is feeding it throughout the day so it is not hungry. What can we do?