How can I advise a friend who is accustomed to drinking alcohol without him resenting the adviser?

You must stop your friend from drinking alcohol, explaining to him that it is one of the gravest sins and that he is exposing himself to Allah's punishment in this world and the hereafter. Explain that the alcohol drinker is cursed by the tongue of the Prophet, peace and blessings be upon him. Make it clear to him that you are advising him out of love for him and eagerness for his guidance. If he responds, then praise be to Allah. But if he insists on that evil, then there is no good for you in his companionship. You should associate with those who help you to earn Allah's pleasure, and let your concern be to please Allah and forbid evil.