As JC pointed out there are 2 of these JWCs.

I think I can account for each of them.

This seems to be the 1893 JWC
IOM Burials

COWIN, John Wilfred 40 Braddan 9 May 1933
Of course, there is no MI

This seems to be the 1896 JWC
Braddan New Burial Ground
Section One
Block 5
# 2953
In affectionate remembrance of AMELIA the beloved wife of JOHN COWIN who died September 28 1866 aged 27 years
Also JOHN ROBERT son of the above JOHN and MARTHA COWIN who died February 12th 1890 aged 11 months
Also THOMAS HENRY son of the above who died August 21st 1910 aged 22 years
Also the above JOHN COWIN who died December 10th 1910 aged 63 years
Also JOHN WILFRED son of the avoe Killed in action June 1917
Also MARTHA wife of the above JOHN COWIN who died May 8th 1935 aged 75 years
also MARY COLQUIT mother of the above JOHN COWIN who died July 31st 1899 aged 73 years

DJD