this is a very unsettling novella, which takes the horror of drug addiction, child neglect, and domestic abuse and then heaps a supernatural horror on top of it, in case it's just not devastating enough on its own. this becomes an allegory of the cycle of addiction, which is not to diminish or underplay the harsh realities of these kinds of situations; instead it brings a fresh immediacy to a social problem that is such a familiar headline, there's a danger of desensitization. this story makes sure you're still horrified by this reality, can still feel outrage. 
 it is very effective, and there are some incredibly uncomfortable scenes, so if you have delicate sensibilities, you should stick to something else. 
 the author has worked in the addiction counseling field for a number of years, and has seen some shit he can't unsee. as a piece of (figurative) exorcism-fiction, i imagine it was very cathartic. it's not always easy to read, because the subject matter is harsh and inevitable, but it is not without ... i wouldn't call it hope exactly, but something that means less than "hope" and more than "justice." probably something there's a word for in german. 
 read it if you dare!!