Thanks Snifter, but that is good info. What were your circumstances for getting the Emergency passport, (sorry, if too personal don't respond), from reading the High Commission webpage we assumed an emergency passport would only be in a serious case such as bereavement and they would need supporting evidence as proof.
In any case he will have to contact the High Commission if he gets turned away by the airline, which from the previous posts is highly likely, and explain his case.
Thanks again to everyone who offered advice and comment, it has all been well received and I guess we will find out in about 24hrs if he gets the flight, or not.