Final answer:
The father's specific occupation prior to the Khmer Rouge is not mentioned, but professionals and intellectuals were targeted during the regime.
Step-by-step explanation:
Before the Khmer Rouge, the father might have had various types of jobs as there is no specific information provided in the given references about his occupation. However, it is important to note that under the Khmer Rouge regime, professionals, intellectuals, and skilled workers were targeted and often killed. The Khmer Rouge aimed to transform Cambodia into a completely agrarian society, so people with non-agrarian occupations were considered a threat to their vision.