I'll avoid the obvious jokes about spiritualism however us mere mortals tend to require mundane things like dates:
approx date of birth of your grandfather would help - remember that latest census is 1891 - do you have a copy of the Maughold Monumental Inscription for the grave ?

Callow is a relatively frequent name on Island (eg there were 44 William Callows in 1881 census)

Name Dumfries is not found in 1881 census

you may find http://www.ee.surrey.ac.uk/Contrib/manx/famhist/genealgy/intro.htm a useful start