The family has released images of a dirty foam mattress on a floor in a house with boarded windows to highlight his plight.
Sister says there is no excuse for her autistic brother’s taxpayer-funded home to be in such a degraded state.
Photos have revealed the squalid conditions in which an autistic man is being kept "like a caged animal" at a disability care unit in the Waikato.
The man's family released the images - of a dirty foam mattress on a floor, in a house with boarded windows and virtually no furniture - to highlight his plight, in the hope he may be found somewhere better to live.
It comes just a week after the Herald revealed the case of another autistic man who had been held for five years in isolated conditions on a mental health ward in Porirua, despite recommendations he should be released.
The Waikato man's sister says while she knows her brother can be violent, and struggles with communication, that was no excuse for his taxpayer-funded home to be in such a degraded state.
"It's just disgusting. It made me feel ill. He's like a caged animal," she said. "Surely we can do better than this?"
The man, who the Herald has chosen not to identify, has severe autism and a mild intellectual disability. He likes to spend time drawing, watching DVDs and sometimes cooking, although the kitchen in his house was removed after he caused it significant damage.
He has been in care since he was 16-years-old, when his violent episodes became too much for the family to handle.
The unit he lives in is run by disability support provider Community Living with funding from the Ministry of Health via a needs assessment agency.
That agency, Disability Support Link, said it was working with the family on a solution.
"When we became aware of the problems with [his] accommodation and that he was unhappy there, we worked with [him], his current providers, and the Ministry of Health and started to look for other accommodation options," Barbara Garbutt, the director of older persons and rehabilitation, said.
"We now have a housing option for [him] and his family to consider and will work with them to find him somewhere better to live."
However the man's sister said the option they had found, which was in Taranaki, was not suitable and the new provider did not have enough information about man to give him the right kind of care.
She said he needed a more secure facility that was better designed so he couldn't cause so much damage, such as smash-proof windows and a larger outdoor area.
"It's clear he can't live where he is now. I wouldn't put my dog in there. But where can he go?," she said.
"They're just setting him up to fail again."
Co-founder of Autism Action NZ Kim Hall said she found it unsurprising the man lashed out given the situation.
"His living conditions are disgusting, there is no justification for it," she said.
The Ministry of Health's group manager of disability support services, Toni Atkinson, said the care facility had been audited recently and the provider had met the terms of their contract.
Ms Atkinson said Community Living had made several recent changes to the property, such as refitting the bathroom and shower to better meet the man's needs.
"Some individuals present a high level of challenge, particularly in terms of treatment of their physical environment," she said. The minimal furnishings were to assist with safety, she said.
Community Living did not comment other than to say it supported the Ministry of Health's statements.