Conversation so far:
who was the last known civil war veteran
Albert Henry Woolson was the last known surviving member of the Union Army who served in the American Civil War
what was Albert Henry Woolson's rank
Albert Henry Woolson was ranked as a Drummer boy.
what years did Albert Henry Woolson serve
Albert Henry Woolson served from 1864 to 1865.

Question: how did the veteran pass
Self-contained rewrite: how did the veteran die