Mohit Dupar died last summer when he tried to save a teenager from drowning at Camber Sands.
The 36-year-old, who ran a construction business, was swimming with his son Ankush when he saw a stranger struggling to stay afloat.
The last words he said were: "Somebody needs my help."
Mr Dupar was pulled from the sea and passed away in hospital four days later. Yet his death and bravery were unknown to the public for three months until it was discovered by ITV Meridian.
18-year-old Ankush Dupar almost died too. In this exclusive report he returns to Camber Sands for the first time since the tragedy to speak to our Correspondent Derek Johnson.