How did Ponyboy grow harder in The Outsiders?

The Curtis' seemed to be one big happy family in S. E.
Hinton's The Outsiders before the mother and father died in an
automobile accident. All three of the brothers' lives changed drastically afterward.
Darry had to forego a possible college football scholarship, working several jobs in
order to support his younger brothers. Sodapop quit school and began working in a gas
station. As for the youngest, Ponyboy may well have had the hardest time. He was
constantly in conflict with Darry, who tried to keep Pony on the straight and narrow
because he knew that his future could be a bright one. Without his parents, Pony began
hanging out more with his greaser friends, and gang fights became a part of his life.
Like his pal, Johnny, Pony was beaten by the Socs early in the story, and he always
feared for his safety when he was on the streets. After Johnny and Pony were attacked in
the park, the two left town to avoid arrest; their dramatic rescue of the children from
the burning church helped to make them heroes. But Pony lost his best friend when Johnny
died, and Pony became more cynical about life. He lost interest in school, and his
friends worried that he would become hard and tough, like Dallas Winston. In the end, it
became apparent that Darry's strict ways were only in Pony's best interests, and he came
to understand how much Darry loved him. When his English teacher gave Pony a second
chance to complete his late work, Pony decided to put his thoughts into words--in the
form of The Outsiders.