The 35-year-old Portglenone man was told in July 2016 he had only months to live after the discovery of a Grade 4 brain tumour.
Family and friends rallied round and after a fundraising campaign launched by his wife Natasha, a staggering £205,000 was raised for a pioneering treatment called immunotherapy.
Kevin started his treatment in London in August and his wife had been keeping everyone updated on his progress via their Facebook fundraising page Kevin Carey's fight against brain tumour.However in recent days - April 29 - a sombre post told the devastating news.
"In March, very suddenly, literally over the space of a few days, Kevin became very seriously unwell. We got an urgent scan, and received absolutely devastating news. Kevin's treatment has suddenly stopped working...the tumour is back again...and there is nothing that can stop it this time. Kevin's medical team are devastated, and as shocked as we are. Kevin was doing so incredibly well.
"Kevin is so strong, so calm and is comfortable, I am so proud of him...and we are being really brave, in facing this devastating news, and stage of Kevin's courageous fight."
The post called for well-wishers to "pray for Kevin that he doesn't suffer, and please pray for strength for him... his family, mine, and all those who love him".
The post added: "Thank you for all your love, prayers, company and support. I am so sorry to have to tell you this heart breaking news, it has been so hard to take in Xxxx
"We respectfully please ask for some privacy for Kevin..his family, mine and his loved ones at this time, whilst we come to terms. Thank you so much xx"