My freind is addicted by drinking wine and drugs

In maximum case a man fall in such addiction due to some sort of failure in life, may be in love ,may be in job..by any frustrating moment.As a friend,I think you should find out his problem and try to divert him whenever he thinks of it.You sometime should talk to him with emotion..sometime sympathetic.But never let him remind the things for which he was sad. Just stay with him. also consult to doctor about his problem