I wonder if he could be related to these two Cunningham brothers ?

I don't have access to A* right now .... but might be worth a shot !
In Memory of
Private T CUNNINGHAM
267855, 1st/6th Bn., Black Watch (Royal Highlanders)
who died
on 24 October 1918
Son of James Cunningham, of 9, Links Rd., Leven, Fife.
Remembered with honour
THIANT COMMUNAL CEMETERY
In Memory of
Second Lieutenant A P CUNNINGHAM
M M
2nd Bn., King's Royal Rifle Corps
who died age 25
on 19 September 1918
Son of James and Janet Penman Cunningham, of 9, Links Rd., Leven, Fife.
Remembered with honour
BRIE BRITISH CEMETERY