A Manhattan Appellate Division judge ruled today that Brooke Astor’s swindling son and his co-defendant estates lawyer can both stay out of jail for the duration of their appeals — a process that could take years.

The decision was especially good news for 85-year-old Anthony Marshall, who has argued in court papers that his frail health would turn any prison time a potential death sentence.

The decision, by Judge Helen Freedman, means that Marshall and co-defendant Francis Morrissey will not have to turn themselves in to begin prison terms when they return to court January 19, as originally scheduled.

Marshall was sentenced to one-to-three years prison on Dec. 21, following his conviction in October for stealing millions of dollars from his Alzheimer’s-stricken philanthropist mother.

Today’s decision followed a 30-minute closed door session this afternoon between defense lawyers and prosecutors, who argued that Marshall and Morrissey fail to meet a vital criterion for bail-pending-appeal — namely, that their appeal stand a good chance of prevailing, according to a source familiar with the session.

Judge Freedman ordered that both defendants post $5,000 bail. She also hiked from $100,000 up to $500,000 the amount the pair have promised since they were indicted that they’d be obligated to forfeit if they abscond, the source said.