This story goes into the idea of peer pressure on numerous occasions. First is the phone call Lorraine made to Mr. Pignati. She did not want to keep the conversation going and felt as if she was not doing the right thing. Her friends kept pressuring her to continue the conversation and so she did.
When she and John later on go to visit him after their scheme of collecting money for charity, Lorraine has the same feeling of guilt. She does not want to take money from this poor old man, and says to John how it is wrong. Not listening to her at all, he pressures her into taking the money and keeping silent about the truth.
Finally, John and Lorraine are pressured into having a party at the house.  This results in the destruction of all of his possessions and him ultimately feeling broken.
With peer pressure running high in this story, many of the characters were unable to speak their own opinions and were afraid to stand up against the crowd. Whether it is Lorraine afraid to stand up against John, or John afraid to stand up to his friends, the main characters are reluctant in speaking their true emotions. The pressure given to them by a massive audience becomes the reason for the downfall of their great friend, The Pigman.
The occurrence of losing loved ones and loved possessions is frequent throughout the novel. It begins with The Pigman's loss of his collection of pigs  and his wife's dress. Both these items were very important to him, letting him remember a time of peace and happiness. When they were both destroyed, he lost a huge part of who he was.
The Pigman also loses his best friend, Bobo.  His death at the zoo was too much for this man, resulting in a heart attack that killed him. His death was the kids losing their dear friend, but also their innocence. The loss of their friend and watching him die was a huge traumatic experience for them, whether they acknowledge it or not. Losing a friend is a very difficult thing for a person to go through. It becomes even harder when you lose a friend and believe that it is your fault. The amount of terrible and shocking experiences Lorraine and John put The Pigman through were too much for him, especially because of his old age. His last stitch of happiness died along with Bobo, leaving him a former shell of himself. When he finally died, his death was a loss to the kids, but not to himself, because he had been unhappy. 
"Family and Parenting"
Throughout the story both John and Lorraine do not know a parental figure. Physically both of them have parents (John having his mother and father, Lorraine having her mother), but mentally they are not there for them.
John's parents do not care what he does and are very self-centered. Both let him smoke and drink and show him that there will be no repercussions for his actions. This makes John take part in troublesome actions, simply trying to get his parents' attention. While his efforts fail each time, he does not give up, and ironically only rebels in such a harsh manner wishing his parents paid attention to him.
Lorraine only lives with her mother, due to her father leaving them a long time ago. Her mother is not a great parental figure, mocking and ridiculing her daughter constantly throughout the story. Her mother's abusive nature strikes fear into Lorraine. She knows if she does anything wrong she will be hit as a repercussion. This is shown when Lorraine states, "She came towards me, and I backed away until I was cornered by the wall. Then she raised her arm and slapped me once across the face. She tried to hit me again,but my arm went up and blocked her." 
Whether physically or emotionally, death recurs throughout this novel. The most apparent sense of death in this novel is the physical. Numerous characters in this story die. Some of these include The Pigman, his wife,  Lorraine's mother's patients, Lorraine's father, Bobo, and John's Aunt Ahra. While some of these deaths are treated as non-important information, they are all are tragic. Losing someone who you are close to or even someone you just know can take a toll on any individual.
This story portrays this message with the final physical death in the story, with Mr. Pignati. His death caused a break in not only the story, but in the two main characters John and Lorraine. This leads to the cause of the emotional death in the novel. John and Lorraine have been through a traumatic and life-changing experience seeing this man die. Even though he was older his death was shocking and unexpected to them. This death of a father-like figure to these children emotionally traumatized them, causing a part of their innocence to die along with the Pigman. This emotional death is similar to that of Lorraine's mother. Her emotional distress after witnessing her husband cheat has caused her to become a bitter person and a different person. Emotionally a part of her died when she found out about her husband's affair and when he died. This novel breaks down the motif of death on a physical and emotional level.