Anthony D. Marshall, the son of Brooke Astor who was convicted in 2009 on charges he defrauded his mother and stole more than $60 million, is appealing his sentence in Manhattan Appellate Court tomorrow. Co-defendant Francis X. Morrissey Jr., a lawyer who did estate planning for Astor, is also appealing his conviction on a series of fraud and conspiracy charges, including a count of forging her signature. Since being convicted Marshall, 88, and wife Charlene, once referred to by Brooke as “that bitch,” are social pariahs living on the Upper East Side. “This whole business has just devastated him,” Sam Peabody, a close friend of Anthony since boarding school, recently told The Post, “They don’t go out much. They’ve been through the mill.” Marshall, who was given one to three years behind bars but has remained free on bail pending his appeal, argues there wasn’t enough evidence to convict him, and that a holdout juror was pressured by the rest of the panel to flip against him. He also claims his mother, while failing in health, was mentally competent enough to consent to bequeathing him additional millions. A source adds, “If his appeal is not upheld, Anthony fears he’ll die in jail. But he is confident his appeal will be successful. If everybody who asked for their inheritance a few years early was sent to jail, the prisons would be full of wealthy heirs.”