This needs to be a separate, simple lightweight, piece of software for reasons that will be made obvious.
You could set up an alert for if the program crashes. I'd like at least a loud sound, but would also like to be notified via email if possible. That's a tough one though. You might have to route it through an online system because many people's computers wouldn't support SMTP servers. I'm pretty sure our firewall would block that. So if it just connects to the internet, and has your server send an email, that would be best. But to start, maybe a wav/mp3 file.
Then a different one for render complete. It's a render that Might take 20 minutes, it might take 3 hours. If you're not using time, you may have no clue. So let me go work on something else, and be alerted when it's finished.
Finished the entire queue? Maybe I'll want an alert for that.
The crash one might be the more difficult. SO instead of trying to capture a crash, perhaps you'd have to set it up to watch the software while rendering. If the software stops being a windows service, it's most likely crashed. Not all crashes actually show up in the windows crash report, so I wouldn't count on it. I've had keyshot crash without a trace before. Windows probably just thought I closed it?