Mrs Heaven, a retired nurse, found a letter by an engine room worker who told the electrician’s family that he was seen still working below deck to keep the generators working moments before the Titanic sank.
The retired nurse, from the same Hindley Green area of Wigan where Mr Parr was born, has also just bought a cablegram – a message sent via a submarine telegraph cable – for £3,800 at auction where his employers praised his actions.
She said: “He died a hero and saved many lives.”
The RMS Titanic was travelling from Southampton to New York on her maiden voyage when it hit an iceberg about 370 miles (230km) off the coast of Newfoundland on 14 April.
The cruise ship sank in the early hours of the next day, and more than 1,500 people lost their lives.
Parr, who moved to Horwich in Bolton when he was eight, had been employed by the Titanic shipbuilders Harland and Wolff for several years in Belfast.
The new father, whose daughter Dorothea was born just three months before the tragedy, was part of the Titanic’s Guarantee Group.
It was an elite group of trouble-shooting workers who helped build the ship, and worked directly for managing director Thomas Andrews.