The High Court has heard how Errol Graham, who starved to death in 2018, was left at risk of "serious harm" by the government, after his benefits were stopped
His body was found in his Nottingham flat in June 2018 when bailiffs broke in to evict him.
His family, which has brought the case, says that the Department for Work and Pensions' handling of his case was unlawful and breached his human rights.
Alison Turner, his son’s fiancée, says that equality legislation was breached because his mental state was not considered as a factor when he missed a fitness for work assessment and did not answer phone calls or answer the door to home visits. She is claiming the government puts the onus on vulnerable people, who may be too ill to do so, to have to prove why they have missed appointments.
Barrister Adam Straw told Mr Justice Bourne the claim concerns "a well-recognised cohort of [benefits] claimants who are unable, because of mental disabilities, to engage with, or respond to the DWP".
He said claimants are "frequently unable to respond to or engage with the DWP because of mental disability or illness", with rejected applications presenting "a significant risk to their health".
He continued: "It is a momentous decision which will often entail a sudden and complete loss of income - leaving the person destitute without food and housing.”
"Withdrawing benefits for a vulnerable claimant like Mr Graham will often put that individual at risk of serious harm."
The judge will give his ruling at a later date.