Mortality is pretty much front and center in Age of Iron as far as themes go. No sooner does the novel begin than we find out that the narrator, Mrs. Curren, is dying of cancer. Throughout the novel, we see Mrs. Curren reflect back on her life and try to come to terms with her rapidly-approaching death. The homeless man Vercueil might even be a sort of Angel of Death. Even though Mrs. Curren's death is the one that we spend the most time contemplating, though, we really seem to be surrounded by death all the time. Bheki and four others are murdered, and their bodies are publicly displayed as a political statement. Later, some officers shoot John to death in Mrs. Curren's house. We don't just watch different people die; we encounter a whole spectrum of deaths, from slow, painful, but relatively peaceful ones, to violent, hateful, and fundamentally unnecessary ones.
Vercueil is actually the Angel of Death.
Vercueil is someone who was in the right place at the right time when Mrs. Curren needed help facing her inevitable death.