If you end up unsure about these things sometimes you need a hand to think laterally about the transferable skills you may have as well as to look at your interests and aptitude.
Your friend probably needs to get some advice and there are plenty of careers advice companies who charge, or go to the State funded option at
http://careersadvice.direct.gov.uk/
It is worth him taking a bit of time to look at this carefully, after all, this is the beginning of the rest of his life........