Hi and welcome.
I'm very much not an expert on these things, just a co-stumbler on the path of life.
It would appear to me that yes, you can quit using one drug -- but what good does it do you if you're abusing other drugs that devastate your life and your relationships in the same way, just maybe not as quickly or expensively?
I wouldn't say that someone who trades one drug of choice for another is "clean" -- not by a long shot. Or "cured" -- I don't think alcoholics or drug addicts are ever cured.
And I don't know how close you are or how much this affects your family -- I grew up with an aunt and uncle who were alcoholics, and even though I didn't live with them, just hung out with them and interacted with them at family events, their alcohol abuse affected me in quite major ways.
I think educating yourself regarding the effects of alcohol abuse on the family is useful and necessary for anyone alcoholism touches. I wish I had realized earlier how it affected me, because it would have saved me a truckload of trouble.
I'm sorry I don't have anything more useful -- but I would suggest reading the posts on top of the forum; they really do have a wealth of information.