Will the intervention stop alcoholism?

It helps. An "intervention" is often the first step in treating alcoholism or addiction. The most important aspect, however, is the persons own desire to do something about their "disease". An intervention typically involves a period of in-patient rehabilitation, followed by support groups(such as aa), sometimes therapy and there a host of medicines that may aid in helping one to stop drinking.
Alcoholism. Agree with dr. Passer. I use the analogy "a teacher teaches students, but does not necessarily make them learn".
No. An intervention is just the first step. In my practice and over the years, I have successfully detoxed over 2000 patients. Detox for me is the easy part. The hard part is figuring out a way to help the person in the long run to stay away from alcohol. There are several medications available now as well as support groups and other modalities for this condition, which can be chronic and severe.