In 1892, both Cushing and his daughter Edith were included in Ward McAllister's "Four Hundred", purported to be an index of New York's best families, published in The New York Times. Conveniently, 400 was the number of people that could fit into Mrs. Astor's ballroom. His New York residence was at 29 East 39th Street in Manhattan. He was "one of the best-known habitues of the Metropolitan Opera House. He and his daughter had orchestra stalls, and they never missed a performance. They were regular attendants at all the Sunday concerts." He was a member, and governor, of the Newport Casino, where he attended many dances, balls and social functions. He was also a member of the Knickerbocker Club, Manhattan Club, Metropolitan Club, Country Club, and of the Somerset Club of Boston.
Cushing's wife died in May 1887. Cushing was injured in Newport in 1900 "when he was knocked down and trampled on by a horse." He died in New York City on June 6, 1902. His estate, including his "horses, harness, jewelry, silver plate, furniture and other household effects," was left in trust to his daughter.
Residences
On December 3, 1870, Cushing bought a property with frontage on Marlborough and Dartmouth Street from George Wheatland, Jr. in the Back Bay neighborhood of Boston. He then had a residence, known as 163 Marlborough, built by architect Snell and Gregerson, who also designed the Concord Free Public Library. Cushing lived in the home until winter 1892 when he moved to Newport, Rhode Island, and rented the home to U.S. Representative Charles Franklin Sprague. He eventually sold the home to William Endicott, Jr., son of William Crowninshield Endicott in 1898. Forbes's cottage in Newport was situated next to Frederick Vanderbilt's Rough Point cottage, and was called "New Lodge." His cottage was described by The New York Times as "on of the handsomest of the fashionable residences of that resort". After his death, his daughter used the Newport cottage with her husband. Cushing and his wife built their Newport residence, designed by prominent society architect George Champlin Mason, Sr., in 1869. Following Cushing's death in 1902, New Lodge passed to his daughter. In 1916, she sold the estate to Frederick Lothrop Ames Jr. and his wife who remodeled the cottage in a classical revival style which they then referred to as Ames Villa. In 1931, Jessie Woolworth Donahue, the daughter of Frank Winfield Woolworth and mother of James Paul Donahue Jr., bought the Villa and renamed it "Rock Cliff." As of 2013, the home was owned by Samuel Mencoff, the founder of a Chicago private equity firm.