Very few children at that young age behave with such maturity, especially in my society they tend to be more "dispersed"....
The education of the parents obviously plays its role, your nephew is obviously very supported although his energy is his own.
I will not disown my niece even if we don't share the same musical taste obviously, she is also very loving and kind, and I will try to keep in touch with her however I can.
Happy Sunday evening to you