What are examples of actions taken by Donny that reveal his nature in Teenage Wasteland?

Donny could easily be classified as a troubled teenager. 
However, it is important to note that none of Donny's actions are actually witnessed by
the audience.  They are all only spoken about through other
characters.  Description of his actions which justify the "troubled teenager" label
include poor academic performance at school, lying to his parents, cutting class,
smoking at school, and drinking (or the smell of beer on his
breath).

His attitude appears to change, briefly, however,
when Donny begins meeting with his tutor, Cal.  Given just a small encouragement to open
up, it seems Donny is willing to at least talk about some of the problems his parents
are concerned with.  He plays basketball with the other kids and seems to be enjoying
himself.  However, by the end of the story, it is clear that if he made any improvement
or headway during his three days a week with Cal, nothing was permanent.  By the end of
the story he has once again been expelled from school.  He says he was basically
blackmailed (with beer in his locker) but this is never proven.  After his transfer to a
public school, Donny disappears one day, and the story ends.  It is to be assumed that
he feels as misunderstood and alone at the end of the story as he did at the
beginning.