What are his chances? (spoilers)
At the start of the film, Brendan's in for twenty years without parole (twenty-five, after he takes out Dave the rapist on JR's behalf). Add to that an escape, a helicopter hijacking, a multi-million dollar bullion robbery, the killing and maiming of several police officers in the resulting shootout, the murders of Sam and several of his cronies (assuming they could pin those on him) and numerous firearms offences.
So at the end of the film, when JR sends him a letter to tell him his share of the gold is buried in a grave in Darwin, what are the chances that Brendan's ever going to get out of prison to claim that money?
And on a semi-related note: After the escape, Brendan and the others find out (by listening to the radio) that Merv was in prison for raping a schoolgirl (and not GBH, as he'd claimed). Did it strike anyone as slightly unlikely that a man with Brendan's connections (both in and out of prison) wouldn't know what one of his most trusted henchmen was really inside for?