I've experienced two outcomes.
The first where they outright did it wrong, imagine someone not understanding basics like variables and parameters, so they just hard code everything and copy and paste all over the place.
The manager said this was fine, since it made our metrics look better, and I ultimately left over this.
In another case, they basically all listened to me and I got to lead a few initiatives. I did have to help out every now and then, but they caught on quickly.
I think Python and JavaScript are learnable within a month. Wouldn't say the same for Java or C#. Personally I still don't touch the most difficult languages, Rust, C++...
My logic is that if I'm personally reaching someone for a month that'll be more effective than putting them in a classroom for 12 weeks.
It's like a foreign language, you can acquire a vocabulary of several thousand words using flashcards over a month, but that doesn't mean you're going to be able to actually communicate.
I mean we're talking about someone doing my job and just replacing me, not necessarily doing everything I can do. I'm sure there are things they might be able to do that I can't. I'm just a midlevel. I assume there are a fair number of "entry level" folks on here. I'm over 10 years in and "entry level". It seems the bar is quite low for most jobs if you have the right credentials or connections (but I pretty much don't).