no medhead... with all due respect... and what you are not appreciating, is the difference between account closure, and termination of membership.
membership is terminated on the death of the member. qantas does not need to be notified of that. it is a fact that occurs, without anyone's action, on the death of the member. their account may still be open... but they are not a member. because they're dead.
their points are also cancelled at the same time as death. their account may still be 'open', but the points are cancelled.
there is no action required (other than the member dying) for the points to be cancelled. even if they are sitting in the account, they have been cancelled. they are just sitting there, but cannot be used (as per QF terms and conditions).
notification is irrelevant for all purposes other than account closure. and the points are already considered cancelled at the immediate time of death.