Well, yes. It wasn't public housing, owned by the government. Somebody in the private sector owned it. Whether it was an individual flat that was owned, or the entire building that was owned, somebody owned it.
NYC apartments are peculiar. Getting into a rent controlled building is a coup, because it's very expensive to rent there, even in a poor economy such as the early eighties. If it was not rent controlled, and was such a deal that he could almost immediately sublet, legally, somebody did him a favor, and that somebody likely knew he was coming.
So, you might take some of the mystery away, from at least one benefactor.
Thanks. I wasn’t thinking about the whole building when I asked the question but I wasn’t sure if people could actually buy their own individual apartment back then. I know absolutely nothing except what I’ve seen in TV shows or movies about renting and buying apartments in New York or other big American cities.