Forgive me if I'm wrong but it sounds like this bloke was failed during line training which means he has already completed sim training and gained an A320 endorsement. That is what his $30,000 was for and so of course he should still pay it*. Not only did he receive the training but he got something at the end of it, so he should pay as he agreed to. That he couldn't make the grade during the line training is unfortunate but some guys just don't have what it takes and if the Colgan crash has taught us anything it should be that a poor pilot should NOT be given too much leeway in training and checks. Fail once, ok you might have had a bad day, fail again where thousands more have passed then perhaps you need to rethink your career choice.
*I don't like pay for training schemes at all, but if you agree to pay then you must pay.