This happened many years ago as my son was only 2 1/2 years old. I believe that he had a connection with my Gram who passed right around the time I got pregnant with him. He knew things that he shouldn't have that only my Gram would know.
Anyways as I was saying, He was aroung 2 1/2 years old and I had 3 month son as well. The way our house at the time was set up was my husband and my room was connected to my childrens room with no door. One night, my husband and I were sleeping when we both woke up to what we thought was our son saying "Hello." We turned on the light and looked around and he wasn't there. He was in his bed fast asleep and of course our baby was not talking. It creeped us out but we just brushed it off.
From that night on he would NOT sleep in his bedroom. He would sleep in the living room by himself or in our bed but not his. Even when my husband and I tried laying in his bed with him he would not sleep in there. It was a nightmare to not know how to help him or even know what he was going through. We tried everything and he wouldn't talk about it. So about 4 months later my mother in law wanted to come stay with us and our landlord had a bigger house come open so we did move. He was fine in that house. And of course we never dared talked about anything with this to him or in front of him.
A few years later, he and I were just sitting around talking and coloring and he looked at me and said "Mommy, do you remember when we lived in that one house and that old man and little boy would come visit me. That old man took pictures of me and that little boy all he would say to me was 'Hello'." I was pretty freaked out.
My landlord at the time ended up selling that house so we had to move again. At the new place we had heard that a woman was said to have killed her husband there. And my son would see a man in a long black coat and a black hat walking around. Although he never bothered my son.