Totally relate, this was confusing for me too as I wouldn't have considered my parents to be 'big drinkers' at least by mine and my (24 hour party people generation) peer's standards.
Fact remains though that there was plenty of alcohol around in my childhood. And plenty of traumatic incidents. They just made a concerted effort to drink less when we moved back here (age 10).
And still there was some alcohol and plenty of traumatic incidents. The real issue was mental illness (NPD e.g.) and having done relentless research it appears to be also rooted in childhood trauma.
I've looked inside the book on Amazon too, I get made vibes from it. I know that my truth and the healing is there. I'd be so grateful to work the steps of ACoA like you wouldn't believe...