She died as a result of her injuries following an attack off the coast of County Sligo by the Provisional IRA targeting her son's father-in-law, Louis, 1st Earl Mountbatten of Burma, in August 1979.

Doreen was born on 29 May 1896, the third child of George Ulick Browne and Agatha Stewart Hodgson (1867–1965), granddaughter of William Forsyth QC.

On 30 December 1903, her grandfather, Lord Henry Ulick Browne, succeeded his elder brother as 5th Marquess of Sligo.

[2] On 27 August 1979, the Dowager Lady Brabourne was seriously injured in an explosion which killed Lord Mountbatten (the father of the wife of her younger son), their teenage grandson Nicholas, and local boy Paul Maxwell, on Donegal Bay, County Sligo.

A bomb had been planted in Lord Mountbatten's fishing boat by a member of the Provisional IRA.