The 21-year-old has muscular dystrophy, a degenerative disease that slowly breaks down muscles, paralysing the sufferer.

The day begins with Josh's carer – usually his dad Rick or mum Tanya – switching off the ventilator which helps him breathe overnight.

Then comes dressing, bathing, toileting, including "logrolling" to put his clothes on. Josh is then hoisted on to his wheelchair, ready to be fed breakfast and face the rest of the day.

The process is repeated at night to get him back into bed.

According to his GP, Josh's life expectancy is less than five years.

Yet, last month Centrelink suspended his disability support pension [DSP] after Josh's parents missed a deadline for a medical review proving he was still unable to work. 

The government is reviewing 90,000 disability support recipients for their eligibility after welfare changes in the 2016 federal budget, with 30,000 undergoing medical assessment.​

Last week, Fairfax Media revealed Centrelink asked a man with severe disabilities and in state care for 17 years to prove his inability to work.

This week, the joint parliamentary committee of public accounts and audit launched a public inquiry into the effective monitoring and reporting of the disability support pension as part of its probe into risk management, and whether public money was used in an efficient, effective, economical and ethical manner.

Federal MP for Bruce, Julian Hill who raised the issue in Federal Parliament this week, is also the deputy chair of the committee. He said the government must change their approach to ensure Centrelink wasn't persecuting the severely disabled with "wasteful, badly targeted reviews".

"So far the government has simply denied there is even a problem and refuses to act despite a growing number of horrific cases," Mr Hill said.

"People with concerns should speak up and submit to the inquiry so the committee can get to the bottom of what's going on and force some common sense on the government."

But Human Services Minister Alan Tudge said the review ensured DSP was given to those "who need it".

Mr Tudge said the department reviewed those most likely to be no longer eligible, based on information, including length of time on DSP without review and incomplete records.

He said Josh was granted the pension before changes to the assessment in 2012, and his record did not show a "manifest disability".

Mr Tudge said Josh was sent a letter asking for a written confirmation of his disability, which was ignored. His pension was reinstated after the department received medical evidence.

"Now that [Josh] has a manifest indicator on his record he will not be subject to further medical eligibility reviews," Mr Tudge said.

Ngila Bevan, co-chief executive, People with Disability Australia, said the "randomness" of the reviews indicated an intention to "scare, intimidate and stigmatise" some of the most marginalised people.

Josh's father Rick said the review was targeting the wrong people.

"Our son Josh has Duchennes Muscular Dystrophy ... and is confined to an electric wheelchair. He needs full-time care," Rick said.

"The only parts of his body that he can move are his hands, fingers and can turn his head when supported with a head rest. He was born with this condition and it will end his life within a few years.

"How can they possibly consider Josh as a borderline recipient of the DSP?"

The Commonwealth Risk Management—Inquiry based on the Auditor-General's report 18 (2015-16) is accepting public submissions until November 7.