Have a look at the Loughborough University website (sport renowned) or maybe Stirling to see what jobs they are advertising.
It could be anything from nutrition to psychology to oxygen uptake/use. Rehabilitation, physio, drug testing/ dope testing.
Maybe not necessarily of interest but how a woman's menstrual cycle affects performance is a big area of research at the moment.
Areas such as event management for the big events, recruiting sponsors, volunteer management, agents for big sport stars.
Any field but just in sport so HR, finance, legal, marketing and PR, advertising, sales. TV sound/camera for the big events.
Ask his coaches what opportunities are available locally to enhance his CV. I'm thinking Park Run volunteer, mascot at home games, waiter for sports hospitality, news reporter, pitch line painter, the person who rakes the sand in the long jump.
I'm sure the London Marathon etc are crying out for volunteer staff. He needs to make contacts.