The family of a mentally ill man who starved to death after his benefits were stopped will take on the government at the High Court later.
Errol Graham’s emaciated body was found in June 2018 when bailiffs broke into his Nottingham flat to evict him.
His family believe the Department for Work and Pensions’ (DWP) handling of the 57-year-old’s case was unlawful and breached his human rights.
They said they wanted to stop the same thing happening to other families.
An inquest into Mr Graham’s death heard his benefits were stopped between August and October 2017.
It was told he had a history of depression and missed GP appointments. He refused help from mental health teams and ignored contact from the DWP.
When his body was found, Mr Graham weighed four-and-a-half stone (30kg) and his family said he had used pliers to pull out his teeth.
Alison Turner, his son’s fiancée, said she believed the DWP breached equality legislation by not considering whether his mental state was a factor when he missed a fitness for work assessment and ignored phone calls and home visits.
She said while the department’s safeguarding policies had been bolstered since Mr Graham’s death, they remained unlawful by putting the onus on vulnerable people to prove why appointments had been missed.
“Although, at first, the DWP maintained their safeguarding policy was lawful, faced with a court case, they have made some changes to the policy,” she said.
“But these changes are not enough. It still falls to the vulnerable claimant to make sure the DWP knows why they have good cause not to respond to inquiries.
“That makes no sense when vulnerable claimants might be too mentally ill to respond.
“For Errol’s sake, I have to challenge this policy so other people don’t suffer in the way that he and our family did.”
Solicitor Tessa Gregory, who is representing Ms Turner at the High Court, said: “It cannot be right that it falls to such vulnerable individuals to prove they had a good cause for not responding.
“The DWP must require their staff, where necessary, to make further inquiries before taking the momentous decision of cutting off what is often a person’s only source of income.
“Unless and until the DWP changes its policies, other vulnerable individuals will remain at risk of serious harm or death.”
The judicial review is being backed by mental health charity Mind, which said the benefits system was “needlessly complicated and stressful”.
A DWP spokeswoman said: “Our sympathies are with Mr Graham’s family. It would be inappropriate for us to comment further at this time.”
The hearing is scheduled to take place over two days.