His grades are poor
He doesn’t do homework
He doesn’t participate in class
His attendance record is erratic
His attitude to teachers ranges from indifference to hostility
He shows no interest in school activities or fellow students
He stole all the baseballs
Principal Merton only tells Luke about all these issues one month before the end of semester! I don’t think it’s just Jess who’s been indifferent to his teachers – they sound like they’ve been indifferent to him as well. It’s almost as if the school has just been waiting for Jess to fail, rather than intervening to help or trying to engage with him – or talking to Luke about all these problems a lot earlier.
Schools really are quite useless in Gilmore Girls. Even if Jess was a model student for the next month, surely that wouldn’t be enough for him to pass, considering he’s had an entire year of doing nothing?
By the way, notice that Principal Merton’s observation that Jess isn’t interested in social activities or making friends at school is very similar to the criticism Mrs Verdinas had of Rory not socialising at Chilton. One might be failing while the other is maintaining a straight A average, but Rory and Jess have more in common academically than people think.