I can't make an obvious connection between my Andrew, who is buried in Monaseed, and your James. Since your family mentioned Monaseed, they're likely to be connected - especially as there were Mahers/Meaghers living in Sleebawn (part of Monaseed parish). It seems that the crucial parish register for 1830ish onwards to about 1850 is missing.
There are two graves in Kilnahue, according to a local book,
Farrell Brislawn d1778 aged 63 and his son Miles d1778 aged 21