There is a Phillip Justen, b abt the correct timeframe - who appears to be the son of Lewis/Louis and Christina Justen in the 1855 census. The 1860 census has Phillip on one page and parents Lewis and Christina and siblings Christina, Margaret, Catharine - on the next page (I don't have access to those census images to see if this is the same family - maybe someone belonging to fold3.com could confirm?)
In 1870 the same children - Phillip, Christina, Margaret, Catharine are living with Davis Justin - girls are listed as servants. Might be a link?
New York, State Census, 1855 Cochecton, Sullivan, NY
Citing this Record "New York, State Census, 1855," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/K6Q7-Z3L
Head Lewis Justin M 48 Birthplace Germany
Wife Christina Justin F 31 Germany
Child Philip Justin M 6 Sullivan
Child Christina Justin F 2 Sullivan
United States Census, 1860 Sullivan, NY
https://familysearch.org/search/record/results#count=20&query=%2Bsurname%3Ajustin~%20%2Bresidence_place%3A%22sullivan%2C%20ny%22%20%2Bresidence_year%3A1850-1860~
Philip Justin birth: 1849 page 120
Lewis Justin birth: 1809 Hesse Darmstadt page 121
Christina Justin1821 Hesse Darmstadt
Christina Justin birth: 1853
Margaret Justin birth 1855
Catherine Justin birth: 1856
U S Census, 1870 Delaware, Sullivan, NY
Davis Justen M 64y Darmstadt
Elizabeth Justen F 60y Darmstadt
Philip Justen M 22y NY abt 1848 farm labor
Christinia Justen F 17y NY abt 1853 servant
Margaret Justen F ? 16 or ? 18y NY servant
Catharine Justen F 14y NY abt 1856 servant
George Justen M 9y NY abt 1861 attends school