If he really wants the job then put him on a bus to Sydney - it's not expensive and he could come home the same day (there is one that leaves Sydney later in the evening)

I'm not sure about the maternity leave issue - aren't you casual? It may be easier to find something new once you know what sort of hours you will be wanting to work once the bub comes, rather than pegging your hopes on a job where you say they don't like you.

And with the bonus - September is still 6 months away - do some maths - is the bonus he will get (remember they tax it pretty heavily) more than half of the increase in income he will have if he moves jobs? It may be better to be getting the money earlier.

I wish him luck in the interview if he decides to go for it.