Mr Burke was allegedly assaulted on August 7 about 1.15 am at the Strathmerton Roadhouse.
Mr Burke is recovering from a brain bleed as well as a broken hip and pelvis, at the Royal Melbourne Hospital.
Mr Bourke's sister Suzanne Hogg from the Mornington Peninsula stepped in to help run the post office before its temporary closure.
“There's so many closures lately due to COVID-19 and the economy so we want to show that Strathmerton will always have a post office,” she said.
“Strathmerton is too big and we are reliant on these services.”
All mail will be redirected to the Cobram Post Shop while the Strathmerton branch recruits a qualified manager to fill the role.
A Numurkah man, 42, was charged with recklessly causing serious injury on Monday, August 9.
He will appear at Shepparton Magistrates’ Court on Friday, August 13.
Numurkah police Senior Constable Scott Ofler said the two men were not known to each other.