Associated Press/Mary Altaffer
The 89-year-old Marshall was granted medical parole after his lawyers argued that he couldn't walk or even stand up by himself and had difficulty swallowing.
Marshall was convicted of defrauding his mother in December 2009, after a dramatic trial that a prosecutor called "Grand theft Astor," according to The Times. The most serious charge he was convicted of was giving himself a $1 million raise for managing his mother's estate.
Brooke Astor died at the 105 back in 2007.