I saw an article from ars that tracked the AI company down, it's registered to the same office as the lawyer, and immediately started advertising this case bragging about it being used in an actual trial, no mention of how much it fucked up and the client was guilty.
He's got a pretty good shot at this, and the lawyer should 100% face consequences. Even if he just used it, but especially if he owns the AI company he used. Doubly so for not disclosing the connection or informing the client it was being used.