Actually, simulation theory (better called a hypothesis) is not a conspiracy theory, it's a probabilistic argument. I don't think its originator believes it is true, but an interesting idea nonetheless.
Whatever your coworker believes probably doesn't resemble what Bostrom was saying, but that's not a reflection on the hypothesis.
https://academic.oup.com/pq/article-abstract/53/211/243/1610975?login=false