Kane McGregor said his family had experienced the worst two days of their lives after Saige, three, and their 18-month-old sister Ashlynn were killed in the Corio fire on Sunday.
His other two children, Mavis, six, and Isaac, four, were airlifted to hospital, where they remain.
McGregor described four-year-old Issac, who attempted to protect his siblings from the fire, as one of the “strongest children (he) has known”.
“Issac had two huddled under him so they didn’t burn,” he told reporters.
“He stayed there until he died himself, (paramedics) revived him and flew him to (hospital).
“I couldn’t be any prouder really.”
Issac suffered burns to 82 per cent of his body and is showing signs of kidney and liver failure.
His sister Mavis is in a stable condition and is due to undergo surgery tomorrow.
“All seems well with Mavis at the moment,” McGregor said.
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“She is a lot less burnt, she should be on the mend soon.”
Their mother Jasmine Beck also received burns to her hands after dragging her children out of the blaze.
It’s understood all four children were inside the shed playing together when a couch caught alight.
Anthony McGregor, who is the brother of the children’s father, told reporters yesterday that Beck was still struggling to come to terms with the loss.
“She’s distraught. She’s not handling herself,” he said.
“She’s trying to be the best mum she can be right now and be there to support her children that are suffering.
“If anyone wants to know how a mother has just lost two kids and has two fighting for their lives is going — if you’re a parent, you know.
“When your kid cuts their hand, you know how it feels to be worried about their child, and this is just multiplied by 1000, by a million. She’s not coping. She’s having a really hard time.”
Police are continuing to investigate the cause of the fire, with McGregor saying a “clicky lighter” could be to blame.
