University guide 2011: Art and design | Education | guardian.co.uk
That should give you a head start and idea on what appears good in rankings, but the rest is down to personal choice. I know a lot of people regard Kingston University as utterly fantastic for Graphics, but others say the way of working there is quite limiting to a designer (lots of group work/hardly any individual projects). Others vouch for the University of the arts London, with Central St. Martins being very popular for arts courses (in particular fashion and graphics) but again, others say that the work produced there isn't of a professional standard and is more conceptual.
Best thing to do is to tell the person who'd be going to check out open days at unis in cities/areas that seem appealing to live in. For example if they'd like to stay up north; Leeds, Manchester, Sheffield. Down south; London, Brighton, Bournemouth.
Check out the university websites, UCAS requirements, order prospectuses, go to open days - do the things that most students absolutely have to do when applying! No one can tell him where to study, he'd have to find out himself
Personally, I found that Bristol was the place for me to study, and that UWE offered everything I wanted in a design course! If he's worried about the prestigiousness of his university, chances are he may not enjoy living in that particular city and do poorly in his degree :/