I'd love to as a urologist that question, lol, but I don't think that's gonna happen.
When I was hitting the gym hard, I would come back from 1-2 week vacations and lift the same weight I had when I left. On a couple occasions, I had injuries sideline me for a month or more, and I'd still be back at full within a week.
It's only when I've been out of the gym for extended periods, ie 6mo or more that I really lost a meaningful amount of muscle mass.
I suspect the bladder and sphincter muscles are similar and that's why the author titled it a 12mo program.
Since you're relying on atrophy, a lot depends on how fast you become able to stay relaxed. A lot also depends on how fast you begin true night wetting, as your muscles will get their workout while you sleep until that happens.
MDL