Hi bow and thanks for using Justanswer.com
Nope, its not about you. You did nothing to cause your children this but you should also know that addiction and alcoholism are bio genetic illnesses. You did nothing wrong and should not blame yourselves, but your boys both inherited the predispostion toward alcholism.
Time to let yourselves off the hook.
If you live in the US and would like a family recovery program that is not blaming and will not cause you more heartache or your sons, let me know where you live and I will give you a referral source.
You have all my very best on this.