Mickey,

The song your cousin is looking for is Abbeyshrule.

The best known version is by Brendan Shine, who has the great artistic distinction (cynical nous, more like) of having released a song about every single county in Ireland. He killed three birds with the one stone when he recorded the gem "Lough Ree, O Lough Ree, where the three counties meet, Longford, Westmeath and Roscommon". Then he started on the towns/villages, which is where Abbeyshrule, Co. Longford comes in.

A search using his name will throw up at least a dozen sites selling his albums. My own search failed to find a site containing the lyrics. Sorry about that.