Ken,
I have also found two Nelson CAIN's in my Burial Book for Douglas Borough Cemetery.
The details are:
Cain - Nelson, age 73yrs, grave no. L101 , buried 29th Oct 1902.
CAIN - Nelson, age 71yrs, grave no. NG 50, buried 23rd sept 1963.

Once again, I hope these help.
Regards,
Carol