The boy's name Malachy is of Hebrew origin, and its meaning is "messenger of God". Malachy (12th century) was an Irish saint. There is a Catholic parish called St. Malachy's in Collyhurst/Harpurhey, Manchester.
Sweeney
Today's name is Sweeney. It is the 51st most popular name in Ireland.
The Gaelic equivalent is Mac Suibhne which means pleasant.