Lawyers would, I suspect, have to prove she believed he was really going to kill himself, and not just making a lame ploy for sympathy as is more common in these situations.

FTA:

Texts show he wavered in his plan to follow through with the suicide, at one point getting out of his pick-up truck.
The court heard that Ms Carter, who was then 17, replied: "Get the f*** back in the car."

emphasis mine

She was only helping him. She gave him the encouragement he needed to achieve his goal.

She's a murderer.

He is too

Been done with myspace bullying. Victim's family won the case.

In civil or criminal court?

In Massachusetts? I think one of the issues here is that goading someone into killing themselves might not be illegal in Massachusetts. So it's a question of law, rather than culpability.

Found guilty of manslaughter.