It sounds similar to something I've heard of Doll therapy being used in Dementia/Alzheimer's disease:
http://www.theguardian.com/social-ca...erapy-dementia,
http://en.benessere.com/psychology/a...ll_therapy.htm
Patients have a life sized, real looking doll that they end up treating like a real child. They don't differentiate between the doll and a real human being.
Although being close to 40, I'm not sure dementia is a reasonable explanation.