I can see James Callow in the 1841 Whitehaven census where ages were rounded (mariner aged 55 b.IoM) with wife Jane aged 50 b. IoM. and 3 children, but do you have confirmation of his age from another record?
They could be James CALLOW & Jane QUINE married 28 Nov.1812 Lonan. This marriage can be seen on LDS film no. 0106728 or in the Manx Museum library, but it would have little further information at that date unless Jane was under the age of 21. - But it would be worth seeing, even if only for the witnesses named, because of the numbers of James Callows.

There were several James Callows bapt c.1786/87 - in Maughold and Ramsey, as well as in Lonan, and many people born in Maughold moved to Lonan.

Do you have any more details about him, to try to identify the right James Callow?

Sue