The child, who cannot be named for legal reasons, died on Friday night in Perth while under the care of the Department of Communities.
Megan Krakouer, Director of the National Suicide Prevention And Trauma Recovery Project, said the boy was removed from his parents' care four days before Christmas in 2020 when they were living in a tent.
But they had created a stable home in the years since and were working with the department in an attempt to reunite their family but it had been unsupportive and judgemental.
"Their hearts are broken," she told AAP on Thursday.
"They are good people, respectful people, loving people."
Ms Krakouer, who is acting for the family, said they felt there had been an incredible power imbalance and the department had ignored them as they attempted to reunite their family.
"They made them jump through hoop after hoop after hoop," she said.
"Some of the words they used were 'grooming the manipulation' and they also said ... they were being looked down upon."
Ms Krakouer said first time the boy's parents had been permitted to see him as a couple since he was removed from their care was at a morgue.
"They're inconsolable," she said.
She said the department had failed the boy and his family.
"Twenty-six case managers over four years and there was not even a cultural safety plan," she said.
Deputy Prime Minister Richard Marles said it was "impossible not to be moved by" the boy's death and it was a "tragic circumstance".
Richard Marles says the death of a 10-year old boy under WA government care is a tragedy. (Lukas Coch/AAP PHOTOS)
"It certainly does speak to the fact that we have enormous challenges going forward in relation to closing the gap," he told ABC TV.
"We really need to be looking at ways in which we can do business in a different way, because the gap is stubbornly persistent.
"News of this kind only adds to redoubling our efforts to make sure we do everything we can to make inroads in respect to the gap."
My heart goes out to the family and community in WA that has lost a son so young. — Linda Burney MP (@LindaBurneyMP) It's shocking, heartbreaking and demands deep reflection.April 17, 2024
Indigenous Affairs Minister Linda Burney said the death was "shocking, heartbreaking and demands deep reflection".
"My heart goes out to the family and community in WA that has lost a son so young," she posted on X.
The Department of Communities has been contacted for comment.
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