The boy asks to speak to the priest. He will go to Wexford to fight as the last of his family. He asks the "priest" to bless him. The real priest had been captured; this "priest" is a yeoman captain in disguise. The boy hangs at Geneva Barracks
Zimmermann 52: "In _The Sham Squire_, pp. 179-180, W.J. Fitzpatrick  tells the anecdote that inspired this ballad." As quoted by Zimmermann the ballad closely follows the anecdote.
Zimmermann p. 39, fn. 18: "In the 1790's those who admired the Jacobin ideas began to crop their hair short on the back of the head, in what was said to be the new French fashion; in 1798 this was considered as an evidence of 'disaffection'."
Hoagland's date range (c.1855-d.1892?) for the auther has a problem; Duffy attributes the ballad to "Carroll Malone" but publishes the text in 1845. Hoagland's attribution to Carroll Malone has that as a pseudonym for William B. McBurney. The article "William B. McBurney aka Carroll Malone" at the "From Ireland" site (copyright Jane Lyons, Dublin, Ireland) agrees that McBurney is the author, that he published it in 1845 and that he died in 1892. - BS
Until Ben Schwartz submitted his note, I had doubted that this is based on any actual incident, but Thomas Pakenham, _The Year of Liberty_, p. 343, notes a case of a Wexford woman with 13 children at the start of the 1798 rebellion. Of her nine sons, five died in battle and three were hung, as was her husband; all four of her daughters were present in the camp at Vinegar Hill, and all came home sick with diseases contracted in the camp. Not the same story, but close. - RBW