It was his first try with the tech. He should have popped the cases into West Law and at least skimmed the briefs, he is at a big firm with that subscription. I'm not a lawyer and I at least have a clue for the legal research shortcuts. This guy must have been drinking and or having an affair to have pit so little effort into his first try using a new tech. I'm guessing there is a risk of humorous legal parody getting scooped up by the chat-bot.
He might not have thought it was a shortcut though.
If he thinks it is like querying a database and had never heard of hallucinations then this could just be an honest mistake. Especially if he thinks AI would be smarter than a database.
My first thought that he was a mess in general but we really don't have enough information. Like the other guy saying he cheated in life, it is pretty absurd to infer that.
My bet would be that he cheated his way through life and the bar somehow and landed the job on the basis of his looks and presentation or who he knew or something like that, so asking ChatGPT and cheating on it was more natural than using actual legal research tools.