Mabel Ethelwyn Harrison ( formerly Borrowes ) of Montreal , wife of Samuel Harrison , plasterer,
died in the twenty ninth year of her age on 23 Sep 1923.
I realise you probably have this and other records but I am hoping that something may come to light by researching around the family.
Edit : I've found the marriage of Mabel Ethelwyn and Thomas Samuel. It confirms that he is the son of Henry Harrison and Elizabeth Kelly :
Thomas Samuel Harrison bachelor , of full age , plasterer of 265 Union Avenue , Montreal ,son of Henry Harrison and Elizabeth Kelly of the Isle of Man , and Mabel Ethelwin Borrowes , spinster of full age , daughter of the Late Robert Borrowes and Ophilia were married on the authority of license 25th February 1918 at Methodist St James , Montreal.