Since you don't have much information and a common name is involved, I think your best option may be to try to find relevant information about the person who emigrated to the US. If you can, get the person's date of birth in Ireland, parents'/siblings' names, entries on Irish census, marriage, etc.
If you can find that person on a passenger list to the US, it may show where they were going to and who they were going to join. There are various websites that have passenger lists, including free ones at
www.familysearch.org and
http://www.libertyellisfoundation.org/passenger.
After that, you may be able to find the family on the US census. 1940 is the most recent one available. You can find them on
www.familysearch.org. New York does not have recent birth records available, but it may be possible to work around that. You may be able to find living people through death records of relatives, obituaries, city directories, etc.