I have seen several Born-in-the-USA Nepalese kids raised in Nepali speaking family, most of them do not even try to learn/speak Nepali.

I have seen several Nepalese in Himachal Pradesh, Uttar Pradesh, most of them speak Nepali with very heavy Hindi accent.

I have seen several Nepalese in Madhesh, most of them still speak Nepali in Maithili accent.

This boy beats them all.  How could he be so fluent in a foreign language just in 4 years?  This boy  is very talented!  He needs help and oppurtunity to move ahead!