Dorothy, why do you think something to Samuel's brother? Is it from family stories or something you have come across?
Samuel and John's mother was showing as widowed by the time of the 1881 census. By the time of the 1891, Mary looks to have remarried, to a Samuel Goodwin. From your family tree on Family Search, I think you have all these census entries?
There was a son showing in 1891, 11 yr old Benjamin R(obert) Goodwin but likely he is from Samuel Goodwin's first marriage (mother's maiden name is showing as Coleman on Benjamin's birth index entry). I suppose, if the story is correct, it could also connect to him rather than John Spencer Cooper.
On the 1911 census, Benjamin is showing as married and living at 7 Victoria (St?) Altrincham. His death, at the age of 58, was registered in 1936 in Bucklow, Cheshire.
Monica