The song itself is fictional, but also highly realistic. For those not familiar with the song, a 17 year old in Canada signs onto a privateering vessel under the British Crown in 1778, going after American shipping. The ship is completely unfit for service and is destroyed by the Americans, with only the singer surviving, but with the loss of his legs, and in 1784 he's a broken man on a Halifax pier in his early 20s. Now what happens to him? Without legs, I presume he can't easily work, especially being an uneducated peasant. I don't know that a privateer could get a pension from the crown. Is there any sort of welfare system at all? Is he relegated to begging? Is there any kind of mobility aid available to him? How does society probably see him?
Follow up question: how could a late-18th-century privateer survive a dismembering at sea? Losing both legs is insane major blood loss, 18th-century surgery wasn't exactly ot stellar quality, and where could a privateer have found a surgeon amongst the wrack of a scummy ship smashed like a bowl of eggs?