I'd expect them to have used AI in the broadest sense of the word, one that includes spell checkers and autocomplete. But, for the same reason AI assists but has not fully replaced us software developers, I think it's not likely to have done more than that — LLMs are one example of AI that's great when you're lacking some skill, it "raises the waterline" so to say, but when you're the best in the business you see all of the flaws in its output.
Why?
Because that's how political messaging is usually curated. I see no reason to expect the Pope to be different. The idea of him finding time to sit down at his desk, doing all that research, finding citations, have time to understand all the technical neauance, etc. etc. sounds totally unreasonable for a person whose time is split in so many directions.
I'm not sure I'm convinced. Why do you think (of all places) the Vatican's press office has taken up using LLMs so quickly? And why wouldn't they mention it (in an official message from the Pope, no less)?
I wouldn't be surprised because an LLM is a viable shortcut to get shit done. Why would the Pope's press office not use one? You think they are too honest, too benevolent to do that? Why?
Because they're not that great? Fine if you have freshman undergrad writing skills.
The assertion says much more about your views than theirs.