If you go to this site, they have a New York Death index
http://www.italiangen.org/vitalreclist.stm

There is a Herman Whitman, age 69, who died in 1930, and a Dorothy Whitman age 63, who died in 1935. These match the ages from the 1920 census.

1905 NY census for Manhattan from www.familysearch.org
Herman Whitman, age 40
Dora Whitman, age 31
Minnie Whitman, age 11
Dora Whitman, age 9
Emma Whitman, age 2

1920 census for the Bronx
Herman Whitman, age 59
Dorothy Whitman, age 48
Emma Whitman, age 16