"It's a tremendous benefit. We have had a real quality of life to enjoy. He knows his five grandchildren," said Mrs Stevenson, speaking from the Royal Courts of Justice in London today after a judge upheld the Nice guidance that people who are diagnosed with early Alzheimer's should not be prescribed Aricept.
Mrs Stevenson said: "I don't know and can't say for sure that it's all down to the drug. But two weeks ago he went back for his six-monthly check-up and his memory had not declined at all. His speech is a little worse but his memory was just the same as six months ago. The drug works for him. It has staved off the worst years for us and given us a little more time together and me a bit more time to prepare myself.
"They do research, they prove a drug works, they put it on the market and now they are going to take it away again. It might not work for everyone, but everyone deserves every chance they can get."
What about the argument that Nice has to make tough decisions to ensure there is enough money left in the pot for drugs and treatments which are more effective? "Come on," says Mrs Stevenson. "It's £2.50 a day.
"In 1977 my first husband died of cancer and he was given every drug available and they were much more expensive. Thirty years on, if John was diagnosed today he wouldn't be able to get Aricept."
Mr Stevenson speaks falteringly. "Without having the medication I wouldn't be able to be here now. It's that bad," he said. "If I didn't have it, it would mean more things I wouldn't be able to do. I need it now so I can keep on running."