Its all very odd! I think likely that he is his brother- something else to investigate!
As for the Molyneux's, all the more confusing looking at the 1891...
Joseph Gerrard Head Male 50 abt 1841 Wigan Lancashire England
Jane Gerrard Wife Female 45 abt 1846 Wigan Lancashire England
Walter Molyneux Son Male 20 abt 1871 Charleston Yorkshire England
Thomas Molyneux Son Male 19 abt 1872 Charleston Yorkshire England
Samuel Molyneux Son Male 15 abt 1876 Warrington Lancashire England
Annie Molyneux Daughter Female 10 abt 1881 Ince in Makerfield
James Gerrard Son Male 5 abt 1886 Ince in Makerfield
Nellie Gerrard Daughter Female 2 abt 1889 Ince in Makerfield