IGI: 17 Jan 1764 John Joseph KEWLEY son of William KEWLEY and Margaret at Saint Barnabas, Douglas
1871 census: RG10/5776 165 pg 14 #49 60 Duke Street, St. Barnabas Onchan
William KEWLEY Head Mar 43 Tailor Master Employ 5 men b Isle of Man
Margaret KEWLEY Wife Mar 45 b Isle of Man
Margaret H KEWLEY Daur Un 19 b Isle of Man
Ann J KEWLEY Daur Un 14 Scholar b Isle of Man
William R KEWLEY Son 11 Scholar b Isle of Man
Elizabeth E KEWLEY Daur 10 Scholar b Isle of Man
John J KEWLEY Son 8 Scholar b Isle of Man
Lucy QUAY Mother in Law Wid 69 Retired from Business b Isle of Man
1861 census: RG9/4417 13 pg 20 #127 16 Wellington St, Douglas
William KEWLEY Head Mar 33 Tailor employing 4 men & 2 boys, b Isle of Man Douglas
Margaret KEWLEY Wife Mar 38 b Isle of Man Onchan
Margaret H KEWLEY Daur 8 Scholar b Isle of Man Douglas
Ann J KEWLEY Daur 7 Scholar b Isle of Man Douglas
Catherine E KEWLEY Daur 5 Scholar b Isle of Man Douglas
Emily C KEWLEY Daur 4 b Isle of Man Douglas
William R KEWLEY Son 1 [listed on next page, nothing else written]
1851: I did notice a William KEWLEY Visitor age 23 [no occupation given] at 55 Sand St, Douglas. Head of household: John QUAY 50 Labourer. Wife Louisa QUAY 40. Son named "Manspah" QUAY 14 and John QUAY 6. Another visitor was Margaret CHRISTIAN 25 servant.
1841: I found the QUAY family but didn't record it. There wasn't a Margaret in this family. There were at least 3 William KEWLEYs in the right age bracket but none in Braddan.
1881 census: RG11/5604 29 pg 10 #39 62 Duke St, Douglas
William KEWLEY Head Mar 54 Tailor Master Empl 5 men, b Isle of Man Braddan
Elizabeth KEWLEY Wife Mar 38, b Isle of Man Douglas [must be 2nd wife]
Elizabeth KEWLEY, Daur 19 Milliner, b Isle of Man Douglas.
1891: no William KEWLEY match
I could not find John Joseph KEWLEY in 1881, when he ought to be about 17. There were a couple of potential "John KEWLEY"s who could be him. Similar for 1891.
This IGI baptism seems late, but warrants checking out:
Margt QUAY bp 8 Aug 1830 Braddan dau of John QUAY and Lucy CRAINE
Only IGI marriage that's close for William and Margaret is:
William KEWLEY and Margaret CRAINE 24 Apr 1851 Braddan.