Hi, and glad you've come to join us.
No alcoholic is completely hopeless, but the odds are pretty bad for one who has NO desire to change.
The best thing for you and your dad to do is to learn how to prevent her drinking from ruining your lives. That IS possible--and some people are able to get sufficient relief that they are able to continue to live with the actively drinking alcoholic. Every situation is a little bit different. But the first step is to learn as much as you can about what you are dealing with, and to find other people who have found solutions to live happy lives.
I second the suggestion that you and your dad try a few Al-Anon meetings. Al-Anon won't help you get your stepmother sober, but it can save your Dad (and you) from being destroyed by her drinking.