When searching for source material I often check Google Books for references to Coffey or, other surnames of interest. I only search "Full View" books because they are typically in the public domain and can be freely downloaded in their entirety.
Today I found the book Irish pedigrees; or, the origin and stem of the Irish nation by John O'Hart, and published in Dublin in 1878.
By clicking on this blog's title link you should arrive at the correct page (page 105) to begin reading about the Coffey family. On the right side of the browser page is a search block. By typing in Coffey and clicking on the Go button, you'll find additional references that may be of interest.