Since I have dealt with alcoholism, to take care of yourself attend Al-Anon meetings. We cannot control what others do, including those we love dearly, but we can take care of ourselves.
An alcoholic gets better by not drinking anymore. A person who drinks because of depression, and most do because of depression, will probably not quit self-medicating until the depression is addressed. A person only deals with this by deciding to deal with it, so the issue is, can you think of a way to get her to see a way out this or see a way to motivate her to take steps to get better?