Dear Craggagh, I looked up the 1901 census & found this - could this be his brother Francis http://www.census.nationalarchives.ie/pages/1901/Cavan/Swanlinbar/Turna…
I also looked up another townland & found this, possible another brother
http://www.census.nationalarchives.ie/pages/1901/Cavan/Swanlinbar/Drumb…
if you look for Patrick's marraige & it looks like he married twice & amazingly his first family were born in Australia, this may assist you & it may tell you who his father is. You can look for records on Familysearch.org (free site) you may find what you are looking for.
Hopefully I have given you some directions to continue on your search.
Do let me know how you get on.
Best Wishes Carmel O'Callaghan