I looked up your ggrandfather on several data bases (Irish genealogy.ie, Roots Ireland and Ancestry) and also his wife's parents. Maurice White and Mary Holmes and found nothing. I believe you need to know a little more about the place they came from before the searches will help.
I suggest looking at all the US records you can find. Often on the emigration certs or ships manifesto or death and marriage certs you will finsd a vital clue. There are many Edmund Barrys born around Fermoy -Cloyne- Middleton area in the decade he was born but without a clue as to his parish or townland or his parents names it will be difficult to identify him in the records.
Good luck in your search.