If the man is depending on the alcohol to do God's work, then it is not God's work the man is doing. God can only work through someone who has been abandoned to Christ. As such, a person needs to be completely dependent upon Christ in all ways so that Christ can work through him. However, if a man is drinking for support and dependence to carry through difficulty, then that man is putting "beer" before Jesus, and thus is worshiping an idol.
If this man truly loves Christ, he will give all things to Christ including his drinking. Beer will not help him to do God's work, it will only make him vulnerable to the enemy.
Would this man drink if he were driving? Would he drink as a fireman or a doctor or any other live saving activity? In a time of difficulty, will he turn to Jesus or beer? Would he allow a child to drink beer?
As a new follower in Christ, he needs to be discipled in matters of faith. How can he be discipled if the Church does not speak? The Lord has obviously put you in this situation. How can the Lord use you if you resist due to fear?
There is no need to condemn him for His actions. To condemn him is to question his salvation. However, you do need to hold him accountable. Do this in love and humility, as though you were counseling a close friend. Let him know that all he needs is Jesus and that beer cannot help.
If the Lord has put this matter on your heart, then you must also consider that the Lord may want to use you. Jesus may want to speak to this man through you. If that is the case, you must consider this as you could fall into sin. Will you obey?
Surrender this matter to Jesus and ask Him to give you the words to say. May Christ be the one to speak through you. Your friend may not heed the words immediately, but the seed needs to be planted.
In Christ,
Blake