The Jewish Kabbalah serves a central role in this story, which means we are verging on religious mysticism. Now, mysticism is hard to define because religions often contain mystic doctrines as they are, but this story is a perfect example of why mysticism works for many people. Michael is trying to solve an existential problem about injustice, suffering, and death, and he is subjected to human evil on top of all that, so religion is a central issue in his life.
What we see in the plot is that he essential has two options available to him: The religious platitudes about the afterlife, or a more active, mystic religion where he still has some power to do good in the world, instead of sitting around waiting on the afterlife. Just because his mother's beliefs seem shallow to Michael doesn't mean he doesn't love her, but what his Rabbi friend gives him through studying the Kabbalah actually helps Michael to use religion in a way that engages his curiosity and challenges him to try and fight back against injustice.
The baddies in this story are also incredibly religious, and they often use religion as an excuse to do violence, but of course a fair reading of the Bible would obviously negate their terroristic extremism. When Michael decides to summon a Golem from Kabbalah folklore to kill the terrorists, the reader has another dilemma to solve: Is Michael's religious violence justified by the evil he is hoping to eliminate? Or is he just falling into the trap of religious violence?
