Since his arrest in June, Breyer has been ill, and his health has continued to decline, his lawyer, Dennis Boyle, said Monday. In recent years, he has suffered a series of ministrokes, and is being treated for a heart condition and dementia.
Boyle said he had not yet learned what specifically prompted Breyer's weekend hospitalization.
"His health took a significant turn for the worse," he said. "All I know is what the U.S. marshals told me."
In light of Breyer's hospitalization, U.S. Magistrate Judge Timothy Rice on Monday canceled an extradition hearing scheduled for this week and said he would decide the case based upon written arguments.
The judge also reversed a decision denying Breyer bail, citing health concerns.
Prosecutors in Weiden, Germany, obtained a warrant for Breyer last year, alleging that as a perimeter guard between 1942 and 1945 at Auschwitz in Nazi-occupied Poland, he provided vital support to a death camp responsible for the slaughter of nearly one million Jews.
His lawyers have portrayed the Breyer of 1942 as a scared 17-year-old taken from his family farm in what was then Slovakia and pressed into Nazi service. Breyer maintains that as a guard outside the camp, he had almost no contact with prisoners, and has said he had no idea of the atrocities taking place inside.
Boyle reiterated those arguments in a court filing last week, hoping to sway Rice into denying the extradition request.
"Johann Breyer was born in the wrong place at the wrong time," the lawyer wrote. "The persecution of one 90-year-old man who merely wore the uniform of an enlisted member of the SS and went where he was ordered to go cannot atone for the German government's decades-long failure to prosecute those truly responsible."