Hi swingout,
I'm very sorry for your situation.
As others have said, your wife clearly has a very serious drinking problem. I think everyone here will recognise her behaviour and attitude. Generally speaking, it only gets worse, and sooner or later the alcoholic crosses the formerly 'unacceptable' lines of behaviour, one after another. It is up to you to draw firm boundaries and stick to them; sometimes this may actually help bring her to the decision to quit. But please do a lot of reading here and elsewhere, you will see that people generally realise that they cannot DO anything to MAKE the alcoholic stop drinking. You ask "can you help them without changing them?" - I'd say you can't really, but in any case don't you want her to change? Stopping drinking is a HUGE change.
What you can do is to focus on yourself and try your best not to let yourself get consumed by the anxiety and stress she causes you and will continue to cause you until the drastic decision to quit drinking is made. I hope for your sake I'm wrong but I suspect she is quite a way away from it right now. Read more about codependency, about 'detaching', consider Al-anon, take care of your health.
Hope things get better for you and for your wife and child. I'm responding to your post because I feel like I was in a very similar situation quite recently (though I don't have children, which is a big difference). My wife's drinking got worse and worse and she did all kinds of previously unimaginable things. After 2-3 years of ever-worsening stress and misery I asked her to move out and REALLY quit and stay sober for several months before I'd take her back; the story is 'to be continued' ...