Anne Graham is a full-time carer for son Paul and relies on government help
Anne Graham said her son Paul, 18, has been blocked from applying for adult Employment and Support Allowance (ESA) because he will be classed as a child until September - despite finishing school for good this Friday.
Ms Graham, 44, who is a single parent and her son's full-time carer, wanted to cancel Paul's child benefit payments so he could receive the fractionally more lucrative ESA after learning that the family's weekly income could plummet by up to 140 when he makes the transition from child to adult.
But officials at HM Revenue & Customs (HMRC), which administers child benefits, told her that because of the way it's calculated, Paul could not scrap these payments for another three months. The Department of Work and Pensions told her he would only be eligible for ESA after completing formal education.
Ms Graham said although collecting ESA may only make around 30 difference to the family's weekly income, it would be significant as she stands to lose out substantially after Paul leaves school.
"On Thursday he's a child and on Friday he's an adult but the difference in financial support is crazy even though the situation remains exactly the same," said Ms Graham.
"Paul will still need one-to-one care and not be able to speak. We are also due to lose out on child tax credit which makes up a large portion of our benefits and will not be replaced by anything.
"This is very stressful. I've actually been trying to organise Paul's transition from school to adulthood for the last few years to make it as easy as possible.
"It can be really hard because sometimes you feel that you are almost begging and I don't think people in my position should have to do that.
"We are actually saving the government thousands of pounds a week by caring for our severely disabled children at home and I obviously can't work because I am a full-time carer for my son.
"It's a major drop in income and you wonder how they can justify that difference.
"How can they say, 'this is how much you get for looking after a disabled child but now they are a disabled adult you aren't entitled to as much' even though they have the same support needs?" We don't need this added stress. It's hard enough caring for a young lad. Because I have chosen to keep him at home my life is limited.
"Instead of making it easier they just make it harder.
An HMRC spokesperson said applicants should be able to stop child benefits at any point but couldn't comment on individual circumstances, while a spokesman for the Department of Work and Pensions said: "If the mother of the person with disabilities is willing to pass on her contact details, then I'm happy to forward those on to the section that deals with applications for ESA to contact her to see if anything further can be done.
"Normally a parent should not have to stop child benefit payments until after their child starts getting ESA in their own right. Clearly we would want to make sure that a person with severe disabilities gets all the benefits they are entitled to."