I'm unfamiliar with the quote. I've heard people say something similar -- but I probably didn't latch on to it because I wasn't sure about it. Perhaps you can find a line or two in the BB that goes along w/ the idea that would make it an even better quote.
I would hope that there is something we can say that will help encourage them towards "ready."
As I look back on the events to my own "getting readiness" I can remember some specific things that I heard that encouraged me. One was a nice and friendly commercial (I don't remember the exact words) from a large cemetery and funeral home out in Los Angeles -- that became a personal invitation to stop by and get to know them over coffee if I was out drinking while driving -- with the suggestion being that it would be good for us to get to know each other now, since we would probably be meeting each other soon, anyway.

I seemed to hear the commercial every time I turned on the radio!
Also, I can remember during holiday seasons -- when I'd be up for my morning drink, ironing a fresh white shirt to go out an conquer the day -- I'd have the TV on and listening to one of those morning news-talk shows. And, for about a week or so, they were having celebrities and musicians that I knew -- that I had partied with, on the shows, talking about how they found some anonymous outfit that helped them to stop drinking and drugging. It got my attention first, because when I heard it, my thoughts were "Heck! That guy can't be an alcoholic! I've drank w/ him and I drank way more than he did! He was a lightweight at drinking! Why would he want to quit?"
I guess those are like little seeds that get planted in our brain from one source, then another source comes along and puts a little water on it, someone else dumps some fertilizer on it -- and before long, a new little sprout of an idea pops up in our heads.
I remember someone saying something like "there's nothing I can say to make them get sober if they are not ready and nothing I can say to make them drink" -- but, I'm not sure of the validity of it. And, when I have questions about quotes I'll usually just take a pass on them.