My daughter did this as well. I lived in a haunted house with a friend and her family for a while and my daughter was about a year old. She saw ghosts, children and a couple of others. Once about a year ago when she was nearly 3 she kept giggling and talking to a puppy, I asked her if she saw a puppy and she said yes. she said it was a big brown puppy and it was right there (as she pointed). There have been instances where I showed her a picture of my step father that passed before she was born and she knew who he was as well as my grandmother whom she never met and knew who it was in the photos. Children have not grown out of their ability to acknowledge that which is out of the ordinary. As we age we are told that some things just arent possible and that is how we become immune to the sight. Some people prefer it that way, but I read a book once from Sylvia Brown. She said you can ask a young child around the age of 1-2 if they remember their other mommies or if you were their first mommy (nana, grandma etc) and many times they can answer you with a logical answer. At that age it is said that they can still remember (if they had a past life) what events took place in their past lives. WEIRD I know. But try it you might find something interesting..... also, most likely if he is laughing at the ceiling or whatever, I wouldn't worry, it is probably a passed relative that is just coming to visit while they still can, or even a child that resided in the home before or something like that. As long as he isnt afraid you shouldnt be.