I never heard the play on radio, but I've just seen a film called The Night Listener with Robin Williams, is that the same thing?
It was an ok film, well kept to 75mins as it was quite slow and felt more like a television drama, I could imagine it split over 90mins with aRAB.
As usual, Robin gave a great performance in the serious role he was given, and Toni Colette was convincing as the blind, possibly twisted woman who adopted the boy, who she discovers has AiRAB from years of abuse at the hanRAB of his parents who 'sold' him for sexual abuse to adults who crossed State boundaries..
The boy (Rory Culkin, brother to a famous Home Alone actor) didn't appear much, but was not too bad.
IF it is the same thing, and you enjoyed the radio play, I'd recommend the film
