In a section of his court filing entitled "Loss of Independence, Loss of Dignity," Philip describes Brooke Astor's Park Avenue duplex as an apartment with leaks and crumbling paint with a bedroom "so cold in the winter…she sleeps on a dirty, smelly couch in the Blue Room [den]."
Christopher Ely, Astor's former butler, driver, and country home manager, also testified in a written affidavit released with the case file.
"Mr. Anthony Marshall…would complain when he had to replace such things as the roof," Ely said.
"He also objected to the costs of maintaining Ms. Astor," added Ely.
"I think it is a tragedy that she is not being maintained in the style in which she has lived her entire life for whatever amount of time she has left."
The allegations in Philip Marshall's lawsuit paint a stark contrast to Brooke Astor's golden history as a social maven and her lavish lifestyle, which was balanced by a lifetime of charitable donations.
In 1998, President Bill Clinton awarded Astor the Presidential Medal of Freedom, quoting her philosophy: "If you have enough money for three meals a day and you're not too busy, you ought to do something for others."
Astor turned her words into action, giving to charities for decades.
"Mrs. Astor inherited over $120 million dollars upon her husband's death in 1959, and she then spent the next four decade giving over $200 million to deserving charitable organizations," Judge John E. H. Stackhouse wrote in the court papers released Thursday. "She gave money only to New York-based charities, having reportedly stated that the money was made in New York City, so it must be spend (sic) there."
According to historian Justin Kaplan, author of "When the Astors Owned New York," Brooke Astor who created a family legacy of giving money to charity. When it came to philanthropy, Kaplan said, the Astor family was on the stingy side of spending to the fur-trading and real estate fortune built by forefather John Jacob Astor.
"They were incredibly rich and incredible sparing to handing out money to good causes," Kaplan told ABC News. "They were not generous people."
"The way things turned out, it took this woman marrying into the family to help reverse the trend," Kaplan added.
Today, Astor resides at Holly Hill, her country home in Westchester, N.Y. -- and in far better conditions than those alleged in her grandson's lawsuit. On July 21, Judge Stackhouse named Annette de la Renta temporary guardian of Brooke Astor, responsible for her care and lifestyle.
Anthony Marshall will legally rebut the charges of elder abuse, Philip's spokesperson Fraser Seitel said. When asked what Anthony's reaction has been to his son's lawsuit, Seitel said. "Once he issues those papers it will make his side of the story public…you'll get his answer."
As of this writing, Anthony Marshall has not returned ABC News' call for comment. While Anthony is not an Astor by blood, he is her only son and next of kin.
Whether the Astor family feud is actual news or just gossip is hard to determine. But the Astor clan is one of the first famous families in American history.
"The founder of the Astor family … was America's first millionaire at the time when the world millionaire had just been invented," Kaplan said. "[Brooke] is the last Astor, at least in the sense of social and financial prominence."
More broadly, Kaplan added, "the whole notion of 'society' has disappeared from American life" with the Astor lawsuit.
With that, Kaplan implies, the Astor-Marshall lawsuit is not just a crack in the image of the moneyed clan. It's also a reminder that the gilded age of the Astors, with its high life and grand hotels, has passed.