This is a tough question to answer because Mathabane is so unspecific about the father's jobs.
We learn in the first few chapters that he came from the tribal lands and should be "cattle farming" as a Peri-Urban policeman chides him. However, whether he actually was a farmer before he came to the city, we do not know.
In chapter 6, is the first mention of any type of job. "...1966 my father was temporarily laid off his job as a menial labourer for a white firm..." We do not know exactly what he did but can assume that it was unskilled labor.
In Chapter 7, we are told about the "back-breaking" work he had to do on white farms and in the chain gangs digging trenches and roads while in prison - so I guess this counts as work.
In Chapter 29, the mother and the father start up a 'shebeen' to sell beer to earn extra money.
In section three, there seem to be no mention of his father working, unless I have missed something.
Hope this helps.