I suggest you get hold the death notice of Thomas Charles as a start as it could include the names of his children and wife
Depot: KAB (Cape Town archive respository)
Source:MOOC
Volume:6/9/244
Reference:703
Description: Vize, Thomas Charles. Death Notice
Date:1887
The KAB archives also have this file which could help
Depot:KAB
Source:MOK
Volume:1/1/341
Reference:R8/463
Description: Vize, Ernest,Deceased estate papers
Date:1920
regards
Bruce