Ontario has quite a few call centers in his area. They set up there because there aren't a lot of jobs at lower education levels so people are desperate and will take a lot of shit. The pay is minimum wage or just very slightly above it, he won't have a consistent shift, most of the centers are 24 hours so he'll get switched from days to nights based on his attendance and whatever other points. He won't get two days off in a row. It's not as easy to fire someone in Canada as it is in the US so if you don't meet your metrics you lose points and the more points you lose the shittier your shift is which drives the bad employees to either quit or get stuck starting work at 9pm with Tuesdays and Sundays off.
I assume this is the job he got or something similar I can't imagine him being anything other than 1st level support because these companies don't usually outsource their actual important stuff, they use 1st level to run the customer through simple fixes like shutting their computer on and off.
I worked a call center job not too far away from where David is now when I was going through university, like you say there is a lot of turn over which is fine with the company people are very easy to replace, they always have training classes running. Personally I would rather be dead then do inbound tech support again, it's absolutely awful.