He also held directorships in other companies,[1][3] including the Brooklyn City Railroad and American Express.

[citation needed] In March 1900, Pratt was re-elected a director of the United States Mortgage and Trust Company, to serve three years.

[3] In May 1923, Justice Stephen Calaghan[3] of the Kings County Supreme Court confirmed “findings of a special sheriff's jury” that Pratt was unable to conduct his business.

[8] The New York Times reported that this was due to his "age," likely a euphemism for dementia or another variant of cognitive impairment.

[1][3] He personally contributed funds to Adelphi Academy, Emmanuel Baptist Church in Brooklyn, and Amherst and Vassar.

For example, as a trustee of Vassar from 1896 to 1920, he contributed more than $800,000, which enabled development of the college's outdoor theatre, artificial lake, and landscape gardens.

[1] He and Mary Seymour Morris had five children:[11] Pratt was a member of the Alpha Delta Phi fraternity, and the Nassau Country Club at the time of his death in 1935.

Although had been ailing since late 1922, his cognitive impairment was further exacerbated by the death of brother George Dupont Pratt in January 1935.

[1] Private funeral rites were held at Seamoor under Reverend S. Parkes Cadman of the Central Congregational Church of Brooklyn.

Funds also went to the International Committee of the Young Men's Christian Association, as well as Pomona College, and the Presbyterian Church of Glen Cove, L.I.

Located in the Clinton Hill Historic District,[6] it is one of the city's finest examples of Romanesque Revival architecture.

[13] In 2014 an enormous renovation and restoration effort was undertaken and Brazilian American artist Sergio Rossetti Morosini was commissioned to build new staircases in stone, restore the endangered brownstone architectural artwork, including ornaments, the critically worn façade and its decayed limestone walls.

Architectural Digest described it as an “American masterpiece.”[14] Beginning circa 1890, he also maintained Seamoor (nominally a summer estate) in Glen Cove, New York.

In the late 20th century, a portion of the property was donated to the city of Glen Cove for use as a public park.