There was this Korean guy that I used to work with that told me that Koreans have a gene that prevents body odor. The thing was he basically smelled like a high school gym locker room 247. I really didn't know what to say to him.
https://www.printmag.com/daily-heller/american-advertising-w...
As a regular gym goer, what smells is /bacteria/. Fresh sweat doesn't smell bad, old sweat does. Same thing goes for urine.
Wash your body and clothes regularly, you don't need deodorant and it won't save you if you haven't washed your body and clothes.
Underarm BO is a totally separate thing, and he's right that most all koreans and east asians don't need to worry about the bacteria that causes that particular smell.
If you go to korea, you'd have a hard time even finding a place that sells deodorant.
So your old coworker is either in a very small minority group, or just had other hygiene problems that are not specifically underarm BO.