Benitez is fighting to save his job due to the infighting that has seen the Spaniard challenge owners Tom Hicks and George Gillett over their failure to provide the funds for new players this month.
The outspoken Hicks has since driven a further wedge between himself and Benitez by admitting to talks with Jurgen Klinsmann over the possibility of the German replacing Benitez.
Ferguson said of the Klinsmann meeting: "That was a bad piece of business on Liverpool's part. That sort of thing can be very upsetting for a manager.
"As a manager, there are quite a few moments in every week when you're on your own and people don't want to knock on your door because they think you're busy all the time, but you can be sitting there twiddling your thumbs.
"You can fill your time by phoning other managers and doing other things, but there's a lot of time spent on your own and, in moments like that, Rafa must feel very alone.
"How you react depends on what kind of person you are and Rafa seems a stubborn character who can put aside emotion, whereas Martin Jol seemed to be more affected by it when a similar thing happened to him at Spurs.
"I've been very fortunate at United because I have had good directors, people like Bobby Charlton and Martin Edwards, who always supported me very well. At big clubs, it is paramount that the board shows their class.
"Twenty years ago, Liverpool were a closely knit and well-run club and, when Peter Robinson was the secretary, a tightly run ship.
"Obviously results matter and they matter to me and they also matter to the likes of Arsene Wenger. But Wenger had great support from David Dein at Arsenal and I've had great support, too, ever since I came here.
"So there is unity there. You should allow a manager to get on with his job."
Ferguson said: "The important thing is that big clubs should be seen to be big clubs. Most players want to play for Manchester United, Chelsea, Arsenal or Liverpool, but when they see a club that is topsy-turvy, with a divide between the manager and the directors, they might think twice. They want to join a stable club.
"One thing is that Rafa has brought in a lot of his players because of his Spanish connections. Now, if an English manager was to come into Liverpool, that connection is gone."