The town of Killybegs is in the RC parish of Killybegs, not Inver. Unfortunately that parish has no records earlier than 1850. Breslin’s not a very common name in the area. The spelling does vary and you can expect to find Breshlin, Breshlen and Breshland in the area.
I have attached a link to the tithe applotment records for the parish, compiled in 1834.
There was a Conely Breshlin in Glengish and another in Glenargan. Either of those might be your “Condy” (the handwriting in the tithe book was extremely difficult to decipher, according to a comment on the website, so the name may have been mistranscribed)..
Turning next to Griffiths Valuation (1857) I found 6 Breslin households. 4 in Fintragh and 1 each in Drumanoo and Roshin. If you don’t find any other clues you might want to focus on those townlands.
1901 census for Fintragh:
None in Drumanoo in1901. This in Roshin: