You can't diagnose an alcoholic based on how clumsy they are while under the influence. What's a bigger concern is that he's continuing to drink, despite adverse things happening when he's drinking. THAT is a sign of trouble.
I'd suggest you find yourself an Al-Anon meeting. It will help you clear your own head about what you want for yourself and the baby. Growing up in an alcoholic home is HORRIBLE for kids.
Oh, and the answer to your other question is that there isn't much you can do to "help" someone who doesn't want any help. You've expressed your concern, and he thinks things will change when the baby comes. I'd be surprised if there is any change, other than one for the worse. Alcoholism is progressive, and it never gets better on its own.