Hi..Thanks for the question. Alcohol & other drugs/substances of abuse can be stopped by a combined approach of patients own will to stop use of the drug (alcohol in your father s case), use of anti craving or anti abuse variety of drugs & specialized types of counseling approaches known as motivation enhancement therapy, relapse prevention counseling etc. For a detailed description; you can consult a Psychiatrist or visit helpful websites such as alcoholic anonymous, substance abuse & mental health services administration (SAMHSA) etc. As regard to effects, the predominant organ affected by moderate to large consumption of alcohol is Liver which initially manifests as jaundice, vitamin deficiency states & secondarily all organs from pancreas reproductive system, brain & nervous system, heart (depending on duration & amount of alcohol consumption) are affected causing alcohol related illness & death. Hope this helps