I didn't read the cited article, but General Armistead's uncle George Armistead was commandant of the U.S. Army garrison at Fort McHenry, MD during the latter part of the War of 1812. It was then-Major Armistead who lobbied his bosses for a new garrison flag, "so large, the British should see it at great distance."
His wish was granted, he repulsed the British Navy and the flag was immortalized by Francis Scott Key. It's today in the Smithsonian Institution in Washington, DC and we call it the Star Spangled Banner.
Lt. Col. Armistead was interred after his death at Baltimore. General L.A. Armistead was buried beside his uncle.