The 1841 census shows Thomas as 68 (i.e. not rounded).
Married (and of the parish) at Deane in 1798.

Lancashire Death indexes for the years: 1843
MATHER Thomas 70 Farnworth Bolton FTH/3/128

Name: Thomas Mather
Year of Registration: 1843
Quarter of Registration: Apr-May-Jun
District: Bolton
County: Greater Manchester, Lancashire
Volume: 21
Page: 101 

Betty was 60 in 1841 (possibly rounded although Thomas was 68, not rounded).  There appears to be an 8 year age difference between them. 

Betty was 64 when she died, so possibly born 1778


Piece 1462: Bolton, Duke´s Alley (Independent), 1785-1818
Name    Betty Johnson
Event Type    Baptism
Birth Date    23 May
Baptism Date    7 Jun 1788
Baptism Place    Bolton, Lancashire, England
Denomination    Independent
Father    Joshua Johnson
Mother    Esther Johnson

Name    Betty Johnson
Birth Date    23 May 1788
Birth Place    Lancashire, England
Baptism Date    7 Jun 1788
Baptism Place    Bolton, Lancashire, England
Church    Congregational Church, St George's Road
Father Name    Joshua Johnson
Mother Name    Esther Johnson

Lancashire Death indexes for the years: 1842
MATHER    Betty, 64, Farnworth Bolton, FTH/3/12

MATHER, BETTY        64 
GRO Reference: 1842  D Quarter in BOLTON UNION 
Volume 21  Page 93
 

Aged 40 in 1841 census (rounded)
Aged 60 in 1861, born Kearsley

Name:    Rachel Mather
Gender:    Female
Birth Date:    13 Jan 1801
Baptism Date:    5 Feb 1801
Baptism Place:    New Road Independent,Bury,Lancashire,England
Father:    Thos. Mather
Mother:    Betty
FHL Film Number:    0560878 (RG4 2431)

Name    Rachel
Gender    Female
Event Type    Baptism
Birth Date        5 Feb 1801 (Corrected from image)
Baptism Date    13 Jan 1801
Baptism Place    Bury, Lancaster, England
Denomination    Independent
Father    Thos Mather
Mother    Betty

Died after 1871 census

Lancashire Death indexes for the years: 1871
MATHER Rachel 70 Farnworth Bolton FTH/24/67

Aged 35 in 1841 (rounded)
Aged 57 in 1861, born Kearsley

This Thomas from Farnworth & Kearsley is not the Thomas from Stand and Whitefield, born about the same year.

This may be the same Thomas, but living at Rainhill (and if aged 10 when baptised):
Name    Thomas Mather
Gender    Male
Baptism Date    28 Aug 1814
Baptism Place    Farnworth (near Prescot), Lancashire, England
Father    Thomas Mather
Mother    Bettey Mather
FHL Film Number    1655234
Reference ID    1655234
Thomas Mather of Rainhill, Hostler

Died after 1861

Lancashire Death indexes for the years: 1867
MATHER Thomas 63 Farnworth Bolton FTH/18/123

Probate:
MATHER Thomas: 12 June
The will of Thomas Mather late of Farnworth in the County of Lancaster Dyer decesed who died 5 February 1867 at Farnworth aforsaid was proved at Manchester by the oaths of Elizabeth Mather of Mather's court Farnworth aforsaid spinster the Sister and Joshua Johnson of 16 Lissadel-street Pendelton in the county afforsaid Manager of a Weaving Mill the Executors.  Effects under £100.

Name:    Ann Mather
Gender:    Female
Baptism Date:    11 Jun 1816
Baptism Place:    Halshaw Moor Independent,Farnworth By Bolton,Lancashire,England
Father:    Thomas Mather
Mother:    Betty Johnson
FHL Film Number:    0560881 (RG4 820)

Lancashire Death indexes for the years: 1850
MATHER Ann 33 Farnworth Bolton FTH/6/140

Deaths Mar 1850   (>99%)
MATHER     Ann          Bolton     21, 123
or,

Deaths Dec 1850   (>99%)
MATHER     Ann          Bolton     21, 139

Name:    Elizabeth Mather
Birth Date:    10 Mar 1819
Birth Place:    Dean, Lancaster, England
Gender:    Female
Event Type:    Baptism
Father:    Thomas Mather
Mother:    Betty Johnson
Baptism Date:    12 Apr 1819
Baptism Place:    Farnworth, Lancaster, England
Denomination:    Independent
Piece Title:    Piece 0820: Farnworth, Parish of Dean, Halshaw Moor Chapel (Independent), 1809-1837

Name:    Elizabeth Mather
Estimated birth year:    abt 1819
Registration Year:    1894
Registration Quarter:    Apr-May-Jun
Age at Death:    75
Inferred County:    Lancashire
Volume:    8c
Page:    165

Lancashire Death indexes for the years: 1894
MATHER    Elizabeth    75 Farnworth Bolton FTH/60/470

Probate: 
MATHER Elizabeth of Mathers-Buildings Farnworth near Bolton, Lancashire, Spinster died 14 Apr 1894.  Probate Manchester 31 May to James Johnson commission agent. Effects £13 1s 7d.