Video: Meet the 10-year-old Vietnamese boy who swims 50km down the Red River in northern Vietnam

Khanh Quan, 12, Nhan's older brother, is also an accomplished swimmer. 

Quan previously set a record by swimming 29km along the Red River.

The boys are trained by their father, Nguyen Ngoc Khanh, who was the first Vietnamese person to swim 200km from Long Bien Bridge in Hanoi to the Ba Lat estuary, where the Red River flows into the Gulf of Tonkin in northern Vietnam.