The home in Clontarf, north of Brisbane, was set alight just before 2pm on Saturday.
Police will allege a 36-year-old man "used an accelerant to set fire to a house in Weaber St before fleeing".
No one was hurt in the attack, but the property was destroyed, Queensland Police said in a statement on Sunday.
The family home belongs to Ben Beaumont and Michelle Liddle, the parents of murdered Queensland teenager Angus Beaumont.
The teenager died after he was stabbed to death by two boys in a car park in Redcliffe.
His aunt said the family was reeling after suffering "another immeasurable loss" in the fire.
"This afternoon his house was burnt to the ground after someone he knew got into his house and poured petrol all over it and lit a match with my brother, his partner and their teenage son it," Mandy Beaumont wrote in a GoFundMe appeal.
"This tragedy is on the back of, in 2020, when my brother's son Angus was murdered in a car park ... this destroyed our family back then, and this next blow is yet another bad, bad thing."
Ms Beaumont said the family had lost everything in the fire.
"My brother is a gardener and he has now lost all his trucks and his tools too ... they have nothing," she said.
Angus's ashes, kept in an urn in the lounge, are also feared to have been lost to the fire.
Police have charged a 36-year-old Dakabin man with one count of arson.
He will appear in the Redcliffe Magistrates Court on Monday.
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