My 3 years old son is crazy for doing shirshasan. he does it for 4 hrs per day, is this harmful for his health

he always wants to stand on his head, he enjoys doing this, doing shirshasan is now becoming his hobby, what should i do? is this benificial for him or may be harmful for his health , i coudn't understand, what to do? he stands on his head , open his feet in v shape for few minutes and then join them before ending his game. plese suggest me. i want to ask my question fron swami ramdevji , how can it be possible?