Hi Clayton / Malcolm / Brigid , if Father Malcolm was Malcolm Leon Cowin , then he did die on the IOM in 1984 , his death registration is in the District of Douglas.
Strangely he is not on Lawsons site of Burials , checked for Rev , Father , Malcolm and Leon.
If Donna is reading she may be able to help with burial.
Cowin is very much a Manx name, although I cannot find any signs of a birth for him on the IOM

Cheers
David Dwyer