His family have branded the situation "an absolute disgrace" and say it is only now he is able to afford the care he needs.
Geoffrey Mann from Copthorne, Shrewsbury, suffered brain damage after a head injury on a construction site in Africa in the 1980s.
The 67-year-old contracted HIV from contaminated blood used in his treatment and has since developed further health complications including hepatitis B, diabetes and vision problems in one eye.
He claimed disability living allowance until 2017, but he then had to be assessed for a Personal Independence Payment (PIP), which was introduced to replace DLA.
Benefits assessments are carried out on behalf of the Department for Work and Pensions (DWP) by the private contractors.
Assessors ruled he did not qualify for any further payments and his benefits were stopped.
Geoffrey's brother John, 72, of Wem, took his fight to the courts and managed to get the decision overturned following a tribunal hearing at Shrewsbury Justice Centre.
John says it was astonishing his benefits had ever been cut, adding: "He's certainly not employable.
"He has brain damage, his memory has gone and he suffers from blackouts.
"He can't do a manual job because he is too weak. He's underweight, it will take him a long time to get back up."
Geoffrey was awarded £14,000 in back pay, equal to the £150 a week he should have been receiving in disability payments.
John says the money has now allowed his brother to employ a carer so he doesn't have to rely on family members.
He said: "It means he's got someone who comes in.
"She cooks and labels his food so he can just warm them up.
"She does all the cleaning. It's made all the difference.
"But there's lots of people in the same position. There's probably hundreds of people who have no help.
"A lot of people rely on their families but it might depend on what family you have and where they live.
"What he went through is an absolute disgrace to be honest."
Since 2013, people seeking to overturn a benefits ruling must complete a written challenge within a month, known as a mandatory reconsideration.
If unsuccessful, people can appeal against the decision at tribunal.
The DWP said mandatory reconsiderations were introduced to ensure claimants received the right decision without having to go to court.
Critics say the process is confusing, stressful and does not give claimants enough time to gather evidence to support their appeal.
The GMB union, which had offered its help in the case – although it was declined, said: "We're incredibly proud of John and congratulate him on winning justice for his brother.
"He has displayed GMB's core values, never giving up and standing in solidarity with his brother in his darkest hour.
"It has been GMB's privilege to have his back throughout this ordeal."
A DWP spokesperson said: “Mr Mann is in receipt of PIP and we have paid him arrears.
"Decisions for PIP are based on the information available at the time, and if someone disagrees with a decision they can appeal and provide more evidence.”