@cantkeepawayforever that seems a lot of work for your DC to have to do across the vacation. Both my DCs are doing essay based subjects and have never had anything like that amount to do during a vacation.
DS2 (O), doing History, tends to keep around a week ahead of his term-time work by doing the first week of term's reading and essay before term starts and so is able to feel ahead of things all term. He has college collections each term but because he has a good memory and is one of those people - unlike me and his brother - who organises every moment of his time very well, revision never seems to interfere with other things. He's got an extended essay to do as part of his finals plus a thesis but is again well ahead of the deadlines for each. Some will be doing those across the vacation, I think.
DS1 (C) doing English, has a short thesis to do for his Tripos 2 finals, which I think he should be getting on with this vacation. His next term is probbaly his busiest yet. However, he seems to have a scarily relaxed attitude to work and somehow things just seem to get done - often almost at the last minute, yet always making the deadline. He does tend to perseverate and procrastinate, so it seems to help him to take it to the deadline and then do adrenaline-fuelled last minute work. If he can keep all work just to term-time, then he will, as he believes vacations should be holidays from work!
I never see their tutor/ supervisor feedback but they'll reveal bits or mutter something like, "Yeah, it was fine". So I think all is going well.
I do think that some courses involve far more work than others and that no matter how on top of things you try to be in term-time, it's impossible not to find you're working just about all of the time and across the vacations as well.
Meanwhile, DS1 and DS2 have been doing lots of applications related to future career possibilities and it's the uncertainty of that next phase of life which at present seems to be taking more focus than finals.