Because he was being paid. A lot.
What would he think? Nothing. In order to work in dictatorships such as Zimbabwe, not only in central Africa but elsewhere, one needs…how to put in in PC terms… a certain moral lassitude and flexibility. If you don’t mind eating steaks and drinking quality French wine while the oppressed locals are starving and/or getting killed by the people that are paying you, well, it sure is a lucrative business.
You’d be surprised how many Westerners are making a killing doing seemingly innocuous work in central African countries - IT guys, banking/finance managers, pilots, security personnel…even gym staff (!). You just have to have a stomach for it. Around 100k Portuguese nationals are working in Angola which is arguably a family dictatorship run by a very odious father/daughter team.
I also know a guy who owns a ridiculously expensive restaurant in Nairobi, Kenya. It’s absurdly expensive, especially for Kenyan standards but it’s loved by the African nouveau riches and is frequented by elites (ahem) of Kenya and neighboring countries. And the reason for it’s success? It has an all white staff from cooks to waiters, all brought in from Macedonia and the locals get a kick from seeing the typical racial roles reversed.
As far as my friend goes, I missed out on many outrageous (and successful) business ventures thank’s to his connections at Mugabe’s court, whether dismantling luxurious villas of white landowners from 1920s and rebuilding the abroad to trading in precious metals.
As far as Mugabe’s rule is concerned, I strongly suggest watching “Mugabe and the White African”, the entire documentary is available on Youtube (trailer below).