Ds1 is just finishing year 9 so we are waiting to hear about which books they are definitely studying for GCSE. But in short yes, I will re-read (skim) the books, there are lots of videos on YouTube about them and their themes.
For any Shakespeare you have to watch it, no play should ever be read, it should be viewed. We will try to see it live somewhere, if not then a film version.
I have a degree in Eng lit and Dh has an engineering degree but has worked in IT for 20 years. So I help with the history/English side and Dh does the computer science/statistics/maths side.
We tend to talk around the topic, ie Ds did council housing in history which was literally read the sheet and answer the questions. But we also watched a 50 minute documentary on YouTube about a particular council estate where they interviewed the residents, some of whom moved in when they were brand new. I think it helps broadens their knowledge base on a topic.
For SATs we looked at past paper English comprehension, just talked through what his answer would be and checked it against the marking scheme. My sons find maths very easy but struggle with poetry, so we look at inferring and asking what does it all mean.
I certainly don't do the work for Ds1, just talk to him and guide him toward stuff. He is excelling at school.