His smile is adorable, but his parents are worried. He has fallen and cut his head and never cried, he has suffered a laceration of his arm, but he never noticed and kept playing. As I examined him I tried to see if he could feel pain, by pinching him, but he didn't move at all. His dad drew his hand away when I tried it on his dad, but the kid didn't move a muscle.
This is dangerous, he won't know if he breaks something, won't know if he is too close to a fire and could burn himself, won't know when he should stop playing because he is causing pain to himself. When he is small his parents might be able to protect him, but as he grows they won't be around all the time.
Pray that his smile continues, that his parents help him understand his situation and that he can understand and play accordingly.