Praying for your friend,
Read and study the story of Saul of Tarsus who became the apostle Paul. Saul was basically a Christian killer with a rough background that was saved on the road to Damascus. Your friend may need to hear this story and know that no matter what he has done it is forgivable.
While on his way to Damascus to arrest and extradite Christians back to Jerusalem, Saul was confronted by the very One whom he was persecuting (Acts 9:3–9; 22:6–11; 26:12–18). What followed was one of the most dramatic conversions in church history. Saul of Tarsus became the apostle Paul, an ardent missionary to an unbelieving world and a fine example of faithful service in the face of fierce persecution (Acts 14:19; 16:22–24; 2 Corinthians 11:25–26). Saul’s education, his background as a Pharisee, his Roman citizenship, and his unflagging zeal all contributed to his success as a missionary, once those credentials and traits had been subjugated to the lordship of Christ.
Once you tell him the story refer back to Romans 10 verse 9-13
9 because, if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved. 10 For with the heart one believes and is justified, and with the mouth one confesses and is saved. 11 For the Scripture says, “Everyone who believes in him will not be put to shame.” 12 For there is no distinction between Jew and Greek; for the same Lord is Lord of all, bestowing his riches on all who call on him. 13 For “everyone who calls on the name of the Lord will be saved.”
God Bless