Your source seems to contradict 'six buliding collapses per month':
"A six-story building collapsed Friday night in Nairobi, killing at least a dozen people. Several buildings in Kenya have collapsed in the past year. Why?"
"A six-story building collapsed Friday night in Nairobi, killing at least a dozen people. Several buildings in Kenya have collapsed in the past year. Why?"
https://www.youtube.com/watch?v=okPYJ4l-lBI
Only the big ones end up in the media..
But you are right it seems like an overestimate. I found this showing 17 buildings collapsed in eight years, citing a CMU study:
https://www.thenewhumanitarian.org/news/2016/05/02/kenya-s-l...