I have located a 38 year old Thomas Bourke as a single man living with parents on the 1911 census in that area, if it is the same person it means he would have been 87 at the time of his death, which seems to be an exceptional age for the time period, so I am doubting that it is him.
Perfectly possibly he could have lived to that age or even older.
It seems on Thomas' part to be an older age to marry, as most people around the time period would have married in their late teens or early 20's.
Another strange statement
It was quite common, especially in rural areas, for people to marry in their 30s, 40s, etc. Sometimes this was because there were elderly parents or other relatives to look after.
My grandfather's uncle married in his 50s to a much younger woman (his sisters living at home previously rejected all possible wives for him) but he finally got around the problem by building a new house for him and his bride and left the sister in the old family home.
My father-in-law's father was almost 50 when he married and my in-laws were in close to 40 at the time of their wedding because her mother was a semi-invalid and it was only when a younger brother married that she felt able to leave home.
When was your grandmother born? was she the eldest in the family? if not, when was the eldest born? that will give you an idea of a date to start searching back from.