How did Darry try to keep Ponyboy on the straight and narrow in The Outsiders?Not only because he wants Pony to do well in school and stay active.

Following the death of his parents in a car accident,
Darry has little choice but to take over as the head of the household if he wants to
keep his brothers together: As long as they stay out of the trouble, the underaged Soda
and Pony won't be relegated to a foster home. Darry takes his responsibility seriously.
Giving up his hopes for a football scholarship in order to work two jobs to keep money
on the table, he also lays down rules for Pony. Pony rarely goes out on weekdays,
instead staying at home with his school work. Darry knows that if Pony is out on the
streets, trouble can follow. Darry orders Pony to never walk home alone, knowing that
roving Soc gangs will target him. Darry tries to restrict Pony's cigarette intake,
hoping to keep his lungs strong for the track team. Darry expects Pony home at a decent
hour, in part because he worries about his younger brother and the trouble that he can
run into after dark. Darry has second thoughts about allowing Pony to participate in the
rumble, knowing he is one of the smallest boys and not well; but Pony talks his way into
attending the fight, and Darry consents, primarily because he knows the greasers are
shorthanded. Later in the story, Darry agrees that the boys will argue less, partly
because Soda hates taking sides between his two brothers.