I can fully understand the pain that you and your wife as well as the other members of the family must be going through. From what you describe and as it generally happens when a child leaves before 14, the link between his soul and the body had either not yet taken place or was too weak to register much. In such instances where there are not many deeper memories the rebirth is almost instantaneous, usually within a month. It is therefore quite likely that he whom you related as your child is already born in some other family. He came for some very specific experience and hence has transmigrated. It is therefore best that the family moves past the painful experience and, to facilitate that it will be best not to keep anything that would bring back his memory such as photograph, clothes etc.
With prayers that the family finds peace and the departed finds in the new place a happier destiny.
Affectionately,
Alok Da
