Unmanageability is the corollary of powerlessness.
If I can't control their drinking, I can't control the effects on my life.
Not two separate statements: state of affairs + logical entailment.
What else am I powerless over?
Well, when coming to Al-Anon: my own beliefs, thinking, and behaviour.
As a consequence, I could not manage my life: These are the management tools.
Al-Anon gives me back control and the ability to management my life under God's direction and with God's strength.