In 1901 Willoughby lived in house 11, Ballymaglare North, Ballynahinch, Co. Down with his parents and sister Kathleen.
By 1911 Kathleen had left the family home.
His first theatre of war is recorded as France from 2nd May 1915.
As an officer Willoughby applied for his medals on 10th August 1922. He was awarded the 1915 Star, the British War Medal and the Victory Medal.
The London Gazette Supplement dated 28th April 1919 records Willoughby Mathers (Black Watch) being promoted from Cadet to 2nd Lieutenant in the Regular Forces on 11th March 1919.
The London Gazette Supplement dated 24th February 1922 records W Mathers (Black Watch) being promoted from Temporary 2nd Lieutenant to 2nd Lieutenant.
Retirement came in 1957.