The kids see it <all>. The addiction and acting out have occurred in front of them, they will also observe whatever recovery occurs even if they don't understand it- and both have effects.
The drinking and fighting in my family of origin was kept entirely behind doors until the latter got too big to hide, but I knew it was going on and over time the former has become more clear. The emotional & physical isolation between the mother and father can't be hidden. I was out of the house by the time my brother observed my father searching the trash for the empty bottles and my dad moved out months later.
IMHO the best thing you can do is not just get the alcoholic away from the kids, but to demonstrate recovery yourself- which means acknowledging & making amends for the hurt and damage & your part in it as well, not just letting the memory fade. The goal is to NOT have them repeat the cycle in 10 years either as an addict or as a codie.