"He certainly kept the pub in good order, and it costs a few dollars to do that, I can tell you," he said.
"The local publican is always a central figure in a small community, as is the pub itself. It's the place where people meet, and that was certainly the case here."
Mr O'Leary suffered devastating injuries that left him a paraplegic in a fall on December 20 last year, but Mr Brown said he had been his "usual cheerful self" last time he saw him the previous week.
He had continued to take a keen interest in the hotel, and what was happening in the community, until the last few days before his death, however.
"It's been a tragic week for Mangonui, losing Paddy and Barney [the cockatoo that Mr O'Leary bought in Taheke when he moved to Mangonui from Dargaville's Northern Wairoa Hotel in the late 1990s, and who he rescued from the bar when the hotel was threatened by fire in January 2018].
Barney, who had become a popular attraction in his own right, died on Tuesday — possibly as the result of a stroke — at the age of 55.
Mr O'Leary will be remembered at a wake at the hotel on Tuesday next week from 1pm.