Well below average, but not disablingly low. From what I understand, he functions normally, despite missing most of his brain.

But he has a job in the civil service and a wife, which are more useful indicators than a high IQ

Even if his IQ was 100+ it doesn't necessarily indicate other kinds of loss... Everyone knows IQ is a poor metric and that intelligence comes in many different forms.

I'm wondering what he lacks that is not outwardly apparent from his job and family life:

Everyone with a biologically normal brain has potential to use it for sophisticated abstract thought in all kinds of ways... or they can (and for the majority do - not judging) spend their whole life not using much of that potential at all. Does this man have less of that potential? is he actually operating on maximum capacity right now as a civil servant?

There are quite a few examples with IQs over 100 too:

http://www.rifters.com/crawl/?p=6116