Thomas does not appear to have remarried. Instead he may have also died youn, aged 25, buried 4 March 1814, less that two years after his wife.  Perhaps it was suicide!  However, if this is him aged 25, he was only about 16 when he married, so this death is probably another.

Name:    Thomas Mather
Age:    25
Birth Date:    abt 1789
Burial Date:    4 May 1814
Burial Place:    Bolton-le-Moors, St Peter, Lancashire, England
Reference Number:    GB127.L243/1/5/1

Name:    Mary Barrot
Event Type:    Baptism
Baptism Date:    30 Mar 1787
Baptism Place:    Bolton-le-Moors, St Peter, Lancashire, England
Parish as it Appears:    Turton Chapel
Father:    James Barrot
Mother:    Martha Barrot
Reference Number:    L243/1/2/1
Archive Roll:    854

Abode blank (i.e. Unknown) so probably not L.B, G.B or Tobge as most other abodes where.

Name:    Mary Mather
Gender:    Female
Marital status:    Married
Burial Date:    5 May 1812
Burial Place:    Bolton Church
Spouse:    Tho'S Mather
FHL Film Number:    1966745

Name:    Mary Mather
Event Type:    Burial
Burial Date:    5 Aug 1812   N.B.
Burial Place:    Bolton-le-Moors, St Peter, Lancashire, England
Parish as it Appears:    Little Bolton, All Saints
Spouse:    Thos Mather
Reference Number:    GB127.L243/1/2/3
Mary w. of Tho's Mather of G.B.

NOTE: Its strange that the "Burials in June 1812" follow on from "Burials in August".  It appears the images are out of order and the burial is in fact May with burials on the page/image starting 4 May.  The page before ended 9th August.  A following page had burials in May 1812 ending 3rd May.

Name:    Mary Mather
Event Type:    Baptism
Baptism Date:    10 Aug 1806
Baptism Place:    Bolton-le-Moors, St Peter, Lancashire, England
Father:    Thos Mather
Mother:    Mary Mather
Reference Number:    GB127.L243/1/2/3

There were 6 Mary Mather's baptised an Bolton in 1806

30 in 1841, in E Bolton
45 in 1851, born Bolton
53 in 1861, born Bolton
57 in 1865, born ca. 1808 (in family grave)

Thomas Mather (1808-1865) was first in grave, burried at St Peter's, Halliwell, so possibly born in Halliwell.

Name:    Thos Mather
Baptism Date:    28 Aug 1808
Parish:    Bolton-le-Moors, Lancashire, England
Father's name:    Thomas Mather
Mother's name:    Mary Mather
Register Type:    Bishops Transcripts
Reference Number:    Drm/2/21

Tho's S of Thomas & Mary Mather G.B.

In 1865, Thomas died in Halliwell, aged about 56-57.

Thomas Mather
BIRTH    1808
DEATH    1865 (aged 56–57)
BURIAL    St Peter's Churchyard, Halliwell, Bolton
MEMORIAL ID    182051323

Thomas Mather (1808-1865), Sarah Mather (1808-1880), Sarah Mather (1865-1932) and George Mather (1833-1899) are all buried in the same grave. GPR Ref 354115

Lancashire Death indexes for the years: 1865
MATHER    Thomas    57    Little Bolton    LB/32/303

Name:    Thomas Mather
Registration Year:    1865
Registration Quarter:    Apr-May-Jun
Registration district:    Bolton, Lancashire
Volume:    8c
Page:    209
or
Name:    Thomas Mather
Registration Year:    1865
Registration Quarter:    Jul-Aug-Sep
Registration district:    Bolton, Lancashire
Volume:    8c
Page:    216

Aged 35 in 1841, living in Hyde. Not from Cheshire
Aged 41 in 1851, born Edgworth
Aged 49 in 1861, born Hayworth (no such place ?)
Aged 64 in 1871, born Turton Bottoms

Name:    Maria Mather [Mary Mather]
Baptism Date:    15 Jul 1810
Parish:    Bolton-le-Moors, Lancashire, England
Father's name:    Thos Mather
Mother's name:    Mary Mather
Register Type:    Bishops Transcripts
Reference Number:    Drm/2/21

Maria d of Tho's & Mary Mather G.B.
20 children were baptised this day, including Josiah, son of Thtthias & Mary Mather, although not adjacent records so probably just a coincidence and unrelated.

(Also Thomas baptised 28 Oct 1808)

Name:    Jas Mather
Event Type:    Baptism
Baptism Date:    22 Mar 1812
Baptism Place:    Bolton-le-Moors, St Peter, Lancashire, England
Father:    Thos Mather
Mother:    Mary Mather
Reference Number:    GB127.L243/1/2/3

Ja's s of Tho's & Mary Mather of G.B.