I doubt there's any time he could safely have taken a holiday; short-notice weather events are pretty common these days. Did he not have a deputy to cover for him? Possibly not, if he was only working three days himself.
However, £100,000 for three days a week should have allowed him to save a bit for a rainy day. As to what exactly he *did* do, who knows? Perhaps the government should give some thought to what precisely the job might entail, and how to ensure it's done when the boss is away, before advertising it again.