Hi...
Chipping or breaking of teeth is very common in children as the milk teeth are fragile and kids keep playing around and falling.
But to start with you need to find out the cause behind it like it may be because of caries which were untreated, trauma, grinding habits, sports etc.
Next Steps
Consult a pediatric dentist soon
Health Tips
Make sure you are maintaining a good oral hygiene at home like making him brush twice daily, rinsing after meals