Just in case you didn't have them here are Thomas's appearances in the prior censuses (but they don't provide any more clues)...
English 1891 Census
Piece: 2435
Folio: 31
Page: 12
Registration District: 12
Civil Parish: Aston
Municipal Borough:
Address: 270, Park Lane, Aston, Aston Manor
County: Warwickshire
WESTWOOD, Samuel Head Married M 47 1844 Brick Layer Harborne, Staffordshire
WESTWOOD, Elizabeth Wife Married F 49 1842 Dudley, Staffordshire
WESTWOOD, Thomas Son Married M 22 1869 Brick Layer Aston, Warwickshire
WESTWOOD, Sarah E Daughter In Law Married F 19 1872 Africa
WESTWOOD, Sarah A Daughter Single F 18 1873 Brass Press Girl Smethwick, Staffordshire
WESTWOOD, Louisa Daughter Single F 17 1874 Cigar Maker Aston, Warwickshire
WESTWOOD, Annie Daughter Single F 14 1877 Cigar Maker Aston, Warwickshire
WESTWOOD, Lizzy Daughter Single F 9 1882 Scholar Aston, Warwickshire
WESTWOOD, Eliza Daughter Single F 5 1886 Scholar Aston, Warwickshire
English 1881 Census
Piece: 3044
Folio: 15
Page: 23
Registration District: 23
Civil Parish: Aston
Municipal Borough:
Address: 116, Tower Road, Aston
County: Warwickshire
WESTWOOD, Samuel Head Married M 46 1835 Bricklayer Handsworth, Staffordshire
WESTWOOD, Elizabeth Wife Married F 43 1838 Wife Dudley, Staffordshire
WESTWOOD, Thomas Son Single M 12 1869 Scholar Birmingham, Warwickshire
WESTWOOD, Catherine Daughter Single F 11 1870 Scholar Birmingham, Warwickshire
WESTWOOD, Sarah A Daughter Single F 9 1872 Scholar Birmingham, Warwickshire
WESTWOOD, Lizza Daughter Single F 6 1875 Scholar Birmingham, Warwickshire
WESTWOOD, Annie Daughter Single F 3 1878 Birmingham, Warwickshire
WESTWOOD, Eliza Daughter Single F 1 1880 Birmingham, Warwickshire