A few years ago this story was told to my brother by a good friend of his, Bob. I have no reason to not believe that it is true.
When Bob was a little boy of 3 his mother died, leaving Bob and his year-old brother Bill with their father. Their father was a good man, but he could not handle the pain of losing his wife well. He put away all reminders of his lost wife except one picture of her which sat on the mantle. He never spoke to his sons about their mother.
Soon after Bill went to kindergarten his teacher met his father at the grocery store. Trying to be delicate about the subject, this being the early 60's and love affairs weren't talked about, the teacher said that she understood that the family had a lady staying with them. Bill's father was taken aback, as there was no woman staying with them, and he wasn't the type of man who would start the type of relationship. Rather than becoming upset he asked where she had heard this? Bill had told her that there he had been upset about going to school and woke up scared, but that the lady had come and held him in her lap, and rocked him to sleep singing a lullaby. Bill's dad said that Bill must have dreamed it.
When he went home he asked Bill about the lady. Bill explained that when he was upset the lady would come and hold him, tell him that she loved him, and would rock him to sleep. When asked who the lady was Billy pointed out the picture of his mother, and said, "That lady." Although this would seem to be the longing of a motherless boy, future events proved the lady did come to visit.
When Bob was divorcing his first wife he brought his children to stay with him at his father's house. During this time the children seemed to become a little more secure about the happenings in their family. Eventually his daughter, the oldest child, told him that everything would be all right because the lady said so. Again a lady was coming to the children at night when they were frightened, talking to them about their fears, and rocking them to sleep. He showed the picture of his mother to the children, and they said that this was the lady.
The final visit to date was when a lady Bill knew was trying to leave an abusive relationship, and needed a place to stay. Bill let them stay at the family house, as it wasn't being used at the time. Bill's friend told him that she was frightened because the children had told her that there was a woman coming into the house and talking to them at night and rocking them to sleep. Bill brought his photo album over from his home [important as there were no photos of him mom in the old house any more], and showed the children. As they flipped through the album they found the recognized the picture of his mother as the lady who came to them.
Bob and Bill had never told anyone about these visits as they didn't think anyone would believe them. They were sure that their mother hadn't wanted to leave them alone so young, and had stayed with them to guide them through troubled times.