Wikipedia tells the story, it's a bit less dramatic than the IOT version:
Évariste Galois - Wikipedia, the free encyclopediaIf Galois had lived, there's little doubt the history of mathematics would be rather different.
.... As to his opponent in the duel, Alexandre Dumas names Pescheux d'Herbinville, one of the nineteen artillery officers on whose acquittal the banquet that occasioned Galois' first arrest was celebrated. However, Dumas is alone in this assertion, and extant newspaper clippings from only a few days after the duel give a description of his opponent which is inconsistent with d'Herbinville, and more accurately describes one of Galois' Republican friends, most probably Ernest Duchatelet, who was also imprisoned with Galois on the same charges...
Whatever the reasons behind the duel, Galois was so convinced of his impending death that he stayed up all night writing letters to his Republican friends and composing what would become his mathematical testament, the famous letter to Auguste Chevalier outlining his ideas... However, the legend of Galois pouring his mathematical thoughts onto paper the night before he died seems to have been exaggerated. In these final papers he outlined the rough edges of some work he had been doing in analysis and annotated a copy of the manuscript submitted to the academy and other papers. On 30 May 1832, early in the morning, he was shot in the abdomen and died the following day at ten in the Cochin hospital (probably of peritonitis) after refusing the offices of a priest. He was 20 years old. His last words to his brother Alfred were...
Galois story is invariably described as romantic, but "stupid" seems more appropriate. Even a genius can be a fool - especially at age 20.
I was curious about the history of his opponent. The man played a major role in history after all. It's disappointing that he turns out be anonymous.
I could find nothing on the web about the subsequent life of Mr. Duchatelet, though I did find a number of spam sites that copied the wikipedia article. I suppose to track this down one would have to look for descendants, and see if there were some kind of oral family history.