James McCabe was from St Helens, Lancs on Keogh's notes. Casement has him as a labourer before enlistment. The following is his service record (provided we are following the right man). There is a St Helens family that could fit, and is more likely to be correct than with the Widnes family
1895 born 21 Nov at Stanley St, St Helens. Baptised Lowe House, Godparent: Anna...? . He was son of Julia McGhee (1865 - ?) and William McCabe (1865 to 1916). His father was a labourer in an iron foundry, and was himself born in St Helens) as was his father before him. You have to go back a further generation to William McCabe born circa 1798 in Ireland to get their Irish root.
1901 census
James is not among the family here, but is included on their family tree
1911 Census
1912 Jan 30 Attested S Lancs 5ft 6inches tall. Fresh complexion, grey eyes, brown hair. At Warrington. Aged 18 years 5 months. A general labourer of 28 Woodward St, Ancoats, Manchester
1913 May 29 married Margaret McCabe (nee Barnes) of St Helens (Prescot 8b, 1202). Eldest child, James, born 16 April 1915
1914 Sep 11 joined Expeditionary Force in France
1914 Oct 24 Prisoner of War (details removed from record)
1919 Jan 15 Returned to England
1919 Apr 28 Discharged, and later got a 30% disability pension for deafness. Transferred to class Z Reserve
1920 Mar 21 Discharged from Reserves
1926 marriage to Margaret Greenall at Holy Cross
1929 his death could well be the man who died Manchester North (Apr/Jun 8d, 704) aged 35
You might be able to trace a living relative through his marriage to Greenall. There's another Genes link to the McCabes, Pat Mather nee Pat Gaskell, whose realtives possess Robert McCabes Military medals and I believe has a surviving elderly relative who remembers the McCabes