Your DS can go into each university website and navigate past the advertorial UCAS guff (we academics don't write that advertising & we are very ambivalent about it!), and go into the Department/School websites and look at the more detailed structure of each degree.
He should look for how each degree is constructed, what modules are compulsory, what are optional, what areas of staff research specialisms there are, and how that research informs and structures their teaching.
Have a look at staff biographies and what they've published, for example. In the humanities, that feed through from staff research into teaching is generally an indication of the quality of a degree, in intellectual terms. Research-intensive universities will do a lot more of that and so students are taught stuff at the cutting edge of new research (I do this in my 3rd year modules - the kids get to work on what I'm working on for my next book).
He can also probably get a good sense of the range of assessment practices - for example, in my department, we don't do any of the traditional 3 hour, unseen examinations, but we do do a lot of collaborative research presentations, and individual oral exams.