Your friend's real problem is that he wants to run his own life. He doesn't want anyone (including God) to interfere and tell him what to do; he wants to be free to behave any way he wants to.
But he knows that if he turns his life over to Christ, he can't live this way any longer. The reason is because when we give our lives to Christ, we must renounce our sin and begin to follow Him. God calls us not only to believe in Christ as our Savior but to yield ourselves to Him as the Lord and Master of our lives. Jesus said, "If anyone would come after me, he must deny himself and take up his cross daily and follow me" (Luke 9:23).
What can you do? First, pray for your friend. Only God can open his heart and mind, and only God can show him the folly of his ways. Logic alone won't make him turn to Christ, because his real problem is his will. Pray that God will convict him of his sin and show him his need of Christ.
Then ask God to help you be a true friend to him, and to be a witness to Christ by the way you live. Right now, he's only concerned about the present and doesn't see any reason to change. But someday, he'll realize the emptiness of a life that is lived only for self. When that time comes, he'll be more open to the Gospel.