Hate Crimes (motif)
The main theme of the novel is sexuality, and one of the starkest ways in which this theme appears is in the form of hate crimes. In Ari's case, this begins at home, although he doesn't know it yet. His brother is in prison serving a life sentence for the murder of a gay man. Dante is beaten up by a group of thugs who see him kissing Daniel. Both boys are discovering their sexuality and going through the process of coming out to family and friends, and both have examples of the prejudice and hate they may face in their own experience already.
Ari Saving Dante's Life (symbol)
Ari is mystified as to how his dad already knows that he is gay, and in love with Dante, when he has hardly yet realized it himself. His father tells him that when Ari put his own life at risk to save Dante's, he realized—because risking your life to save the life of the one you love is a symbol of deep love. Ari's brave act was a public symbol of his love for Dante.
Secrets (motif)
Everyone in the novel has secrets, and we learn over the course of the narrative that keeping these secrets bottled up rather than getting them out into the open is a bad thing. A prime example of this is the secret of Ari's brother. His parents act as though his brother is dead, and keep the story surrounding his incarceration a secret from Ari. Of course, this just fascinates Ari more, and further isolates him from his parents. Had they told Ari the secret right away he would have felt a closeness with them and realized what strong people they are, and he might also have felt less fascination for his brother. The other secrets that appear are his father's experiences in Vietnam, his aunt's sexuality, and his mother's mental breakdown.
Absence of Relatives (symbol)
At Aunt Ophelia's funeral, Ari realizes that they are the only members of the family present and that everyone else is missing. He learns that Aunt Ophelia has been ostracized and "disowned" for her sexual orientation. The fact that Ari and his parents are the only family members at her funeral is symbolic of the fact that they were the only family members there for her in life as well.
Ari's Dream (symbol)
Ari dreams that Bernardo is across a large river and that although Ari can see him, he cannot reach him. Ari shouts at Bernardo to come across the river and come home. This dream symbolizes Ari's fascination with Bernardo and his longing to have some kind of relationship with him. Although he knows that he is in prison for life and cannot physically come home, the dream symbolizes Ari's feeling that if the family were to talk about Bernardo then he would be able to come home, in that he would be spoken about as if he was a member of the family again.