This is very possible. I think most institutions, ie. Banks and Building societies will pay to the next of kin up to a maximum amount. And if your friend's mother held monies in several banks, etc. then they could easily amount to £30,000. However, in my case I had to have some sort of form from my solicitor than I was who I said I was.
i.e. As Barmaid said, it wasn't only a death cert. I had to produce - I can't remember what the form was that a solicitor had to sign - I got it from the bank concerned.