Thanks, Averil. I had put their marriage on an earlier message, but was unsure which of the burials on BL's list was the right Matthias/Matt, because there were several around the same age. Where did you get your death date from? The burials list has CAIN, Matthias 92 Onchan 16 Apr 1857 who was considerably older than Matthias aged 67 in 1841.

I thought that the 92 yr old was possibly the one who gave his age as 80 in 1851:
CAIN, Matthas Head Widower M 80 1771 Shoemaker b.Onchan
RG number:HO107 Piece:2525 Folio:267 Page:14
Conchan Municipal Borough:
Address:
31, Great Nelson Street, Conchan, Douglas

In 1851 (if still alive) Jackie's potential Matthias Cain would have been 77, so not far off the 80, but suddenly an employed shoemaker? And moved to Great Nelson St?

BL's burials also have CAIN, Mathias 75 Onchan 12 Apr 1853 who I thought was the closest to the one aged 67 in 1841, but one of them is missing from the census, unless he was Matthew aged 73 a weaver cotton b.Conchan living with his wife Ellen 80 at Cronknamona, Conchan.

Actually Jackie, I came across one census entry with some of your family forenames, but probably means nothing! (From Marown):
CAIN, Matthius Head Married M 45 1806 Blacksmith Marown
CAIN, Margt Wife Married F 42 1809 Blacksmith Wife Braddan
CAIN, Matthias Father Widower M 86 1765 Retired Teacher Marown
CAIN, Wm Son Unmarried M 21 1830 Blacksmith Marown
CAIN, Rebecca Daughter Unmarried F 18 1833 Braddan
CAIN, Sophia Daughter Unmarried F 12 1839 Scholar Braddan
CAMNEEN, Wm Head Married M 31 1820 Cart Wright & Joiner Braddan
CAMNEEN, Elzth Wife Married F 30 1821 Cart Wright Wife Marown
CAMNEEN, Cathe Daughter Unmarried F 12 1839 Scholar Braddan
CAMNEEN, Elzth Daughter Unmarried F 1 1850 At Home Marown

RG number:HO107 Piece:2523 Folio:255 Page:17
Address:4, Baldwine Village, Marown

I can't double-check these "CAMNEEN" names because there is "an internal error" to the scans (on Findmypast).

Sue