veryrestless,
You can't control an alcoholic. Your AH is making his own bad decisions, and his priority is his addiction. You are not enabling his addiction. You are better off.
Any birth is a happy event, absolutely joyous. 100%! If your parents cannot find happiness in something that is so wonderful, then there is nothing you or anyone else in this world can do to make them happy. Stop trying - it is their loss. I am not saying you should stop talking to them, just leave it to them to figure out what makes them happy.
You can make your baby happy. Your child's birth has actually made many good people here at SR happy - judging by all these posts!