Moving, causing, surviving. That’s why animals have a central nervous system. And that’s how a religious person ought to lose faith in God: on the move.
Simulation (mimicry) is included under ‘moving’.
The best way for a religious person who already doubts his faith, but doesn’t know how to go on, is to enter into learning relationships with atheists. Such relationships, mediated by goodwill and the sincere desire to learn, allow the religious doubter to ‘try out’ atheism, to simulate it for its effects on self and others. Multiple simulations should be attempted. Slow cure is all important. These experiences must be largely positive to induce attachment.
Sudden and dramatic loss of faith almost never happens, if ever, for the reward system in the brain needs to re-tune itself out of the current attractor-category (religion) and into the new attractor-category (atheism). This change takes time; sometimes years.
To lose faith in God, you need to do something. You do this by first copying others who are already masters of the game.