This is not typical, but is not uncommon. It is usually indicative of insecurity about his relation with his parents. Does he have difficulty separating from you, like when leaving for school or if you go out and leave him with a baby sitter.?
Candidly, the basis of this unfounded fear is not clear and really will require some delving by a professional child therapist to determine the cause of the problem and rectify it. The positive news is that children can make changes quite readily.
If you require further clarification or more information, feel free to ask!
Please click the green "ACCEPT" button on this page if you are satisfied with my answer so that I get credit for my work. Your positive feedback is most important and bonuses are always welcomed. If this is a mental health, or medical emergency, please call emergency services (911 in the USA), or go to your nearest Emergency Room. The opinion provided does not replace an evaluation by an appropriate professional. Use of this website DOES NOT CREATE a provider-client relation and this information is for educational purposes only.
Thank you for your generosity and good luck.