Evidence-based psychological interventions
For friends. Here is some literature that may help. It explains various treatments and indicates which are most effective. Sometimes treatment involves psychotherapy or psychotherapy combined with pharmacotherapy (drug treatment). The review gives an overview of current research. Alcohol use disorder is classified as a substance use disorder. Follow the link https://www.psychology.org.au/practitioner/resources/interventions/ or just view the pdf https://www.psychology.org.au/Assets/Files/Evidence-Based-Psychological-Interventions.pdf.
There is a lot on the internet http://findings.org.uk/docs/Magill_M_2_findings.pdf http://www.australianprescriber.com/magazine/38/2/41/3 but it would be impossible to wade through it all without professional help. Multiple factors need to be assessed and treatment must be tailored. However, be consoled. There is hope. The following is from the DSM-5 "Alcohol use disorder is often erroneously perceived as an intractable condition, perhaps based on the fact that individuals who present for treatment typically have a history of many years of severe alcohol-related problems. However, these most severe cases represent only a small proportion of individuals with this disorder, and the typical individual with the disorder has a much more promising prognosis."