Ghost of Liam
Throughout the novel Veronica is haunted by Liam's presence, hearing his laugh or his voice, expecting him to be there and then realizing that he's dead. She believes that she hears his voice and even sees his face at his wake making her crazy, with the finality of his death and plagued with guilt. Veronica loved her brother as one is supposed to love their brother and his death affected her tremendously, but what haunts Veronica is not his death, but what she believes to be the cause of his death, the abuse he went through as a child, and of which she kept silent.
Religion
Religion is a motif present in the novel. Veronica remembers herself praying and going through a religious phase in her childhood. The problem in that phase what that she liked to ask a lot of questions, like when she asked her father where Virgin Mary went to the toilet, to which she got a slap on the face from her father. Veronica doesn't believe in heaven and believes hell to be emptiness, nothingness.
Grandfather's mustache
Her grandfather Charles died when Veronica was a child. Her grandmother Ada let the children see his dead body in bed, the reason being, Veronica believes, that she didn't want to be alone in the knowledge. What solidified the fact that Charles is dead to Veronica wasn't his unmoving body, but his unmoving mustache. Her grandfather was the only man she knew with a toy on his face, the mustache which moved, dazzled and distracted. The stillness of the mustache is the sign of his death to the little girl.
Death
Death is the main part of the novel, with Liam's suicide and Veronica trying to feel alive after being faced with the finality of it. Veronica is haunted by the impending presence of death, having to gather information on how her brother died, all the details of it, and having to move on, to accept being alive, continue with her daily routine knowing this truth. It is later revealed that it is not only the death itself that affected her, but the truth that she kept and believes to be the cause of his misery.
The gathering
The gathering from the title is to explain the gathering of the family members to say the final goodbye to Liam, the gathering of the Hegarty family with all their imperfections and dishonesty; Veronica who is on the brink of a breakdown, Ernest who is hiding that he no longer priest, or a twin sister that had a surgery to remove the family nose. They all gather around their suffering mother, who, as Veronica realizes, loves some more than others, her being the one her mother barely notices and the discovery of a new Hegarty Liam left behind and on whom all want to clear their consciousness for any misbehavior towards Liam.
