Tell him he has to believe as when a child believe blindly, even if he can't see it, for that is having faith in God. Once he believes and accept Jesus Christ into his heart and ask him to lead him closer to him and his step to the right path, Jesus will take care of the rest if he allows Jesus to guide him. It's not complicated because salvation is free to all who come to him with sincere repentance in their heart. Be careful with him that he may be wanting to use you for some malicious things. May the blood of Christ cover you from all harm.
Lord open this man's eyes, and ears to you, also soften his heart to hear your calling him to salvation. I pray in Jesus' mighty and merciful name, amen.