36-year-old Mohit Dupar was swimming with his son at Camber Sands last July, when he tried to help a stranger struggling to stay afloat in the sea.
The man in trouble was 19-year-old Gustavo Silva Da Cruz.
Mr Dupar was unable to save the teenager who drowned.
Mohit Dupar was pulled from the sea and passed away in hospital four days later. His death and bravery were unknown to the public for three months until it was discovered by ITV Meridian.
His son, 18-year-old Ankush Dupar almost died too. In this exclusive report, he speaks to our Correspondent Derek Johnson.
Watch our special programme on the day the coroner recorded verdicts of 'misadventure' for the seven men who died on the beach last summer.
An inquest is due to open into the deaths of five friends who drowned during a day trip to Camber Sands in East Sussex last summer.