James Reilly was found dead and his sister, Peta Reilly, critically injured in a home at Kuranda on Thursday morning.
Ms Reilly was taken to Cairns Hospital with facial injuries and her condition is now stable.
The siblings' sister has flown to Cairns to be with Ms Reilly, as police investigations continue.
Relatives of two siblings have expressed shock after one was found dead and the other critically injured in a Far North Queensland home.
Police went to the home of James Reilly and his sister Peta Reilly, both aged in their 60s, at Kuranda on the Atherton Tablelands just before 10:30am on Thursday.
Mr Reilly was found dead and Ms Reilly was found with significant facial injuries.
She was taken to Cairns Hospital in a critical condition, but is now in a stable condition.
The siblings' sister has planned to fly from interstate to be with Ms Reilly, who has undergone facial reconstruction surgery.
Police remained at the house and the family were waiting for answers about what may have happened inside the home.
The siblings' nephew, Tim Reilly, said his uncle and aunt had been living in their late mother's home since the 1980s.
"He was very social and generally very well liked," he said about his uncle, James Reilly.
