How is Gabriel different from his twin brother, Danny, in the novel, Who They Was?

Unlike Gabriel, Danny has always been an obedient and law-abiding individual. Sometimes Gabriel resents his brother's close relationship with their parents, and his diligent pursuit of the violin. Though Gabriel occasionally refers to Danny in memory, they only interact in real time once over the course of the narrative. When Gabriel is spending more time at his parents', Danny returns for a holiday visit. He scolds Gabriel for bringing weed into the house, and sides with their mother regarding Gabriel's need for a changed life.