Breyer was born in 1925 in what was then Czechoslovakia to an ethnic German father and an American mother, Katharina, who was born in Philadelphia.
Slovakia became a separate state in 1939 under the influence of Nazi Germany. In 1942, the Waffen SS embarked on a drive to recruit ethnic Germans there and Breyer joined at age 17.
The fact he was a minor at the time was critical in the 2003 decision to allow him to stay in the United States.
Called up to duty in 1943, Breyer said he was shipped off the same day to Buchenwald – in Germany – where he was assigned to the Totenkopf.
By treaty, the U.S. can extradite its citizens to Germany. But Breyer said he would fight any attempts to take him away from the U.S. and his wife and family.
"I'm an American citizen, just as if I had been born here," he said in his Philadelphia home. "They can't deport me."