Psychologically what is real is his personal experience with God prompting him to let go of a vice - the alcohol.
The problem is that in his mind, he is applying his own experience in terms of the world. He thinks that just because God told him to stop being an alcoholic that God wants him to inform the whole world and evangelize. While his intentions are nice, his approach is socially inappropriate.
You need to talk to him and let him know that you really appreciate his intention to try and help out your family members and others and that is a wonderful thing to show his heart is in the right place but that you would appreciate it if he could please stop calling your family members as it is creating lots of stress in their lives.
Be sure to let him know that you really do appreciate and respect his decision to give up the alcohol.