If William died 1855 he should appear on the 1841/1851 Census.
There is one on the 1841, down as age 80, c 1761 in West Bourne, Sussex.
If you look at the image it looks to me that he is age 20, not 80
HO107/1104/2/West Bourne
If you are descended from Issac which a Tree I have seem as the info you posted on it?
Issac is in Broadwater 1851 Census.
I am going to "throw a spanner in the works here"
Marriage;
24 January 1821, St Mary, Broadwater, Sussex
William AYLING, Widower
Rhoda PAGE
(Source FreeREG)
1851 Census has a William Ayling born c 1769, Greatham, Sussex, with a younger Wife Rhoda born c 1785, Billinghurst
HO107/1651/118/16
May be him or not!