The latest probate records on-line for Transvaal are up to 1974 - you could apply to the Masters Office for a copy but you would need the estate file number. A normal Death certificate would not list the parents, an estate file may list the parents, however if they predeceased him it may not as the person filling the form in may simply state they are deceased.
If you know his Identity Number you could apply for a Vault copy of his birth record - that would list his parents. The best way to get a vault copy is to apply through a document retrieval company as they appear to have better luck at getting them.
If you know his birth date and where he was born, and what church he belonged to you may be able to find a baptism on-line.
