Fiercly guarding their plastic eggs

I adopted a male ring neck dove about a month ago, he has a nice cage, plenty of toys and a shelf in my room with food that she can have all to herself. In the day she has free roam of my room and sometimes I will let him fly around the rest of the house for a change of scenery. Although I do have cats so I prefer to keep him safe in my room. He seemed more open to being held in the beginning but is now very scared of me. He will perch near me and be close, but whenever I reach my hands slowly twords him or put my face close to him, he immediately flys away. Because he is scared of my hands he won’t accept treats from me. The treats I have are amaranth seeds and millet and for regular food I have a high quality seed mix. I found out he has feather lice so we went to the vet a twice for treatment. I really want to give him the best life and be able to bond with him but I’m not sure what to do, please help!!