There are many times during The Absolutely True Diary of a Part-time Indian when alcohol abuse affect Junior. Most significantly, Junior is torn when his father's best friend Eugene is killed over a simple glass of wine. The two men had been drunk and had gotten into a fight, and Eugene's killer shot him out of anger. Junior assumes that this would not have happened if the two men had not been drunk, and he laments the fact that so many Indians on the Spokane Indian Reservation turn to alcohol to deal with their lives.
Junior is also really upset when his grandmother dies--she is the only person whom Junior knows that did not drink, and ironically she is killed by a drunk driver. This upsets Junior tremendously because he always confided in his grandmother.
Finally, Junior is left to mourn the tragic death of his sister Mary who dies in a fire because she was too drunk to detect any danger. Junior looks back on the lives of these three important people and knows that alcohol abuse led to each of their deaths. Senseless.