If it’s just a console.log thing, my guess is the language for the code.org site in general didn’t get switched (which can be switched from the home page, scroll all the way down and the lower right there’s a language drop-down menu).
Probably something particular to that computer. I would troubleshoot by having the student log into another computer (that’s been working fine for other students) and see if the problem follows. If so, could be particular to his account. If it doesn’t follow, something may have changed on the browser or computer. Try changing browsers, clearing cookies, etc.
I’ll have a code.org staff member look in on this in case they have some insight. Meanwhile, I think trying the above would help us gather some useful troubleshooting info.