Because I'm learning how to write fiction, I'm going to pick apart its story to help me learn.
The four story lines add interest and carry the narrative forward. They also don't completely work together to create a more powerful conclusion. You could remove the plot line about the house fire without changing the ending. You may lose a bit of insight into Gabriel, but not in any way that makes you less interested. Similarly, Gabriel's girlfriend was unnecessary. The author seemed to agree given the way he wrote her out.
Gabriel himself makes some very impulsive and bad decisions. I hear Anne Lamott pop up in my head reminding me that impulsive and bad decisions are sometimes the thing that drives plot forward. These impulses are somewhat justified later on.
There were two missed opportunities to turn the story into more of a thriller. I wonder why the author didn't take them. Was he trying to subvert convention? I'm reminded of Iain M. Banks' Culture series. Banks loved to subvert story convention, but this sometimes meant that there were story lines that got stuck and went nowhere. Conventional story lines sometimes exist because they are emotionally satisfying.
