I think the action of withdrawing the show is appropriate.
Prank call shows are nasty, snide, humiliating, and deeply unpleasant, especially when anyone who objects is uniformly accused of having no sense of humour.
The two DJ's could not have reasonably forseen such a tragedy - it was and remains a juxtapostion of circumstances that no-one could have anticipated, and as such, they should not shoulder any legal responsibility - i am sure they already carry more than enough moral responsibility.
The station is drawing a line and ,oving on, which is appropriate in my view.