You must know that every child is clairvoyant until the age of four years. Afterwards, the innocent atoms of clairvoyance submerge themselves within the subconsciousness. -Samael Aun Weor
Children perceive things that adults do not because as adults our consciousness is asleep. They can perceive elementals of nature and also egos which do not enter the body until the personality is created.
Conjure and seal your son's room with a magical circle of protection each night using your willpower and imagination. See the reference below for how to perform this practice.