First of all, your friend is the one who needs to make a choice of getting treatment. A lot of times, people get scared of going to a psychiatrist or Psychologist because they are afraid of being judged. Also, your friend has developed a coping mechanism of escape, therefore he numbs his pain and sadness in alcohol and drugs. As a friend, you need to work towards making him aware of his situation. Ask him simple questions like “are you happy” “where do you see yourself in 5 years” “what kind of a life do you want to live” Sometimes simple questions can make one think and be aware to make a choice to get help.