ImperialBlether I did my undergraduate degree followed by my professional (work-related) degree, never once, literally never, did any of my parents proof read an essay or have any input into the actual work. It wasn't the sort of thing they could help with, and wouldn't have known how (non-academic types, never went to uni, in a niche specialist subject). I don't ever recall them helping, or me asking for help, with exam prep or something either.
So lack of understanding or visibility of essay, coursework or exam content isn't always an indicator of someone not going to uni
Unless maybe the student was on e.g. a PGCE to become a teacher and her mum or dad was a teacher, of course - then there might be some oversight (you'd hope anyway).
BTW, wanted to add my voice to the posters saying this is more common than people think - there were 2 people on my course who failed exams, one dropped out completely at the end of 2nd year, and didn't tell his parents - as far as I know they probably thought he graduated.
The other one failed exams in his 3rd year, told his parents he was doing a year-long Masters ("won a fully funded place") at the same uni, but was really re-taking his 3rd year over again. I still know him, and his parents - they talk so proudly about how their son has done multiple degrees, postgrad etc. I'm assuming he has no plans to tell them!