Hi
This in the Cape Town Archives, could be his wife and child:
DEPOT KAB
SOURCE PIO
TYPE LEER
VOLUME_NO 1807
SYSTEM 01
REFERENCE 79601E
PART 1
DESCRIPTION IMMIGRATION PAPERS. MRS. E RANKIN AND CHILD.
STARTING 1956
ENDING 1956
The Cape Town Archives does offer an ordering service but not sure how it would work for overseas requests, here is the email address that I used and found the response to be quite prompt:
archives@pgwc.gov.za or alternatively you can get a researcher to go to the archives for you:
http://www.national.archives.gov.za/on the left of the page you will see a link to professional researchers, scroll down the page until you find the ones that deal with the Western Cape Provincial Archives.
Good luck