Looks like son John?:
Corporal J. Adair, number 15264, 10th Bn. Royal Inniskilling Fusiliers, died 4 Oct.1916, son of Mr. W. Adair 32 Governor Road Londonderry.
If so, more details: assosiated with Christ Church (Church of Ireland), Londonderry. Son of William (d.7 Mar.1946?) & Matilda Jane?
"Corporal Adair's father received intimation from the Reverend Alexander Spence that his son was instantaneously killed by a trench mortar shell while in the trenches. The Reverend J. G. Paton, Presbyterian chaplain and Corporal Adair's major, also wrote, in a sympathetic letter: 'I do not know a braver soldier in our battalion. He had played a heroic part a few nights before in the enemy's trenches, when we captured a machine gun. He was specially commended by the officer in charge.'
John Adair won an Ulster Division Certificate for conspicuous gallantry on July 1, 1916, in the Thiepval sector. Whilst in charge of a bombing attack, on that day, he bombed many dugouts and took many prisoners. His name was read out during a memorial service held, on Sunday, November 4, 1917, for the members of the congregation of Christ Church (Church of Ireland), Londonderry, who had given their lives in battle during the previous year.
William and Matilda J. Adair, 32, Governor Road, both signed the Ulster Solemn League and Covenant (September 1912) pledging opposition to Home Rule for Ireland. William Adair, same address, worked as a Fitter in the Londonderry Shipyard in the early 1920s, and belonged to the Derry branch of the Ulster Unionist Labour Association in the same period."