He paid for an endorsement and got one, where's the problem? If he had these issues during endorsement training and never completed the endorsement then it would be a different matter but why should he not have to pay for an endorsement that he received just because he has failed his LINE training.
If there was an issue with his line training being inadequate then he should be taking Jetstar to court for unfair dismissal and the pilot body could get right behind that, but disputing the $30,000 ENDORSEMENT cost is without merit.