John Marsden Simpson.

Mary's nephew, James' youngest son.
He married at 22.
1887 John Marsden Simpson + Eliza Walsh St John Darwen Blackburn CE139/2/330

Children
1888 Hubert Simpson Darwen Blackburn D/96/26
1893 Reginald Walsh Simpson Darwen Blackburn D/107/15

1881 census
RG11,4207,125,61
Blackburn Darwen 20
7 Primrose Terrace.

Rachel Simpson 22 cotton weaver born Darwen
On the census Rachel is over a crossed out James, maybe James lived here before he married Ann then returned to Primrose Terrace after his little adventure at Cat Leach.
John Simpson 15 brother blacksmith

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1891 census
RG12,3415,151,33
Blackburn Darwen 25
2 Highfield St.
John M. Simpson 26 Blacksmith employer born Darwen
Eliza 25
Hubert 2

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1901 census
RG13,3924,53,1
Blackburn Darwen 33
20 Highfield St.
John M. Simpson 35 Blacksmith employer born Darwen
Eliza 36
Herbert 12
Reginald W. 7

John was living near Thomas his brother, who appears on the next page living on Starkie St.

Using the Parish online Clerk site, John and Eliza had their children baptised at St. John The Evangelist Church, where most of the Simpson marriages seem to have taken place.
They had another son Ralph who died.

Hubert Simpson c.20 Jan 1889 son of John Marsden Simpson + Eliza 2 Highfield Blacksmith
b.7 Dec 1888
Ralph Simpson c. 20 Sep 1891 son of John Marsden Simpson + Eliza 2 Highfield St Blacksmith
b.14 Aug 1891
Reginald Simpson c. 20 Aug 1893 son of John Marsden Simpson + Eliza 2 Highfield St "
b.20 Jul 1893

Using Lanc. BMD
Death 1892 Ralph Simpson age 0 Darwen Blackburn D/62/79