Hi there!

I did not find a passenger list for your Robert Brewer, but I think these listings may be your Brewer family, beginning with the father's death:

England Deaths and Burials, 1538-1991
Name: William Brewer
Gender: Male
Burial Date: 22 Jun 1870
Burial Place: Tingrith, Bedford, England
Source Film Number: 1066961

England, Births and Christenings, 1538-1975
Baptism/Christening Place: CLOPHILL,BEDFORD,ENGLAND
* Father's Name: William Brewer
* Mother's Name: Hannah
1) Name: Robert Brewer Baptism/Christening Date: 17 Oct 1813
2) Name: Mary Brewer Baptism/Christening Date: 28 Apr 1816
3) Name: Charles Brewer Baptism/Christening Date: 14 Sep 1823
4) Name: Henry Brewer Baptism/Christening Date: 30 Dec 1827
Source Film Number: 1279077

* the above are from the LDS (FamilySearch) website.

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found a Robert Brewer in Philadelphia, PA ... not sure if he's "yours" though:

1850 United States Federal Census
Pennsylvania > Philadelphia > Manayunk Lower Ward > (image21)
Name: Robert Brewer
Age: 38
Birth Year: abt 1812
Birthplace: England
Home in 1850: Manayunk Lower Ward, Philadelphia, Pennsylvania (multi-family residence??)
Gender: Male
Family Number: 152
Household Members: Name Age
Robert Brewer 38 (b. Eng) occ: Spinner
Ann Brewer 42 (b. Eng)
http://search.ancestry.com/Browse/view.aspx?dbid=8054&pa...

1860 United States Federal Census
Pennsylvania > Philadelphia > Philadelphia Ward 21 > (image271)
Name: Robert Brewer
Age in 1860: 48
Birth Year: abt 1812
Birthplace: England
Home in 1860: Philadelphia Ward 21, Philadelphia, Pennsylvania (multi-family residence??)
Gender: Male
Post Office: Leverington
Household Members: Name Age
Robert Brewer 48 (b. Eng) occ: laborer
Ann Brewer 55 (b. Eng)
http://search.ancestry.com/iexec?htx=View&r=an&dbid=...

could not find Robert Brewer (or Ann) in the 1870 or 1880 US Census .... could be he went back to England when his father died (?)