Mary and Charles raised William Boyle Jr after his mother died (Elizabeth Curtis). It looks like they even officially adopted him.
The 1851 census lists Mary as 30 years old, putting her birth year at close to 1821. They have a 2 year old son named John at this time.
By the 1861 census, John is gone, and they have adopted William Boyle Junior, Mary’s nephew, whose mother had passed away a few years earlier (and I suspect is Charles’ sister).
In the 1871 census, she is listed as 50 years old, putting her birth around 1821.
The 1881 census lists Mary as born in 1817, age 64.
She passed away from cancer, which was diagnosed two weeks before she passed away (her physician at the time was J. G. Baird). The death was registered on December 19th, 1888 by William Boyle.