Today the Channel 4 newsreader will address the annual general meeting of the charity Counsel and Care, telling about his "dreadful" feelings of guilt at having to put his elderly mother, Joan, into a home.
Alzheimer's disease affects 350,000 people in Britain and is expected to affect 1 million in the next century. It is a physical condition which attacks the brain cells and although diagnosis is difficult, symptoms usually manifest themselves within six months to a year. It affects one in 20 over-65s and one in five over-80s.
Jon Snow's mother, now 87, started to develop Alzheimer's disease 10 years ago, and Jon and his two brothers faced a struggle to try to find a home for her to live in.
As the population ages it is an increasing problem for sons and daughters, who may be experts on childcare, but have little knowledge of how to find a good home for their parents.
"It's a desert out there," says Mr Snow. "We found an absence of support and of course you never have any real sense of who to contact and even when you do find who to contact there's not much information. There's such a lot of sink provision."
In the early stages of the disease, Joan remained in her own home in rural Dorset, with neighbours keeping an eye on her. "It was her neighbours - both much older than my mother - who bore the brunt of what was happening to her," says Mr Snow.
"At first they were desperate to help her stay in her own home. But finally, after a succession of chaotic adventures, we decided she would have to move. They had done a fantastic job to keep her going, but she was hallucinating and in the Dorset countryside there isn't much peripatetic care.
"Oblivious to the gravity of her true condition, we set out to find the most beautiful local surroundings. We came up with two wonderful homes. She was out of the first in a night and out of the second in two. She finished up in Poole General Hospital on drugs. The geriatricians said we had to have her out of hospital and housed in a fortnight."
The main problem the Snows faced was that while there were plenty of residential homes, there were fewer willing to take on an Alzheimer's sufferer who required quite intensive care.
"There were a lot of general old people's homes which were absolutely fine, where people have no problem living a pleasurable existence. The drawback is they don't have the intensive medical care that was needed.
"There's a combination of exploitation and inadequate and inappropriate care for Alzheimer's victims. There's not a lot of good provision and it's only later you discover which is which.
"What happens is that there's a crisis and the individual gets taken by ambulance and put into a geriatric ward and you're given notice to put them into a home. What do you do? The hospital says 'here's a list of approved homes' and you find that they are all full or they don't exist any more or they don't take that kind of patient.
"The first long-term facility we found for her was ghastly. She was locked in every night and my mother has a phobia about being locked in. We were only alerted because a member of staff put their job on the line and told us.
"We wrote to every single social services department in the country and got a list of homes from each. I was ruthless in my refusal to accept less than the best."
Guilt wrestled with reality as each of Joan's sons trudged across Britain in search of a viable old people's home.
"The provision was ghastly almost universally. All over the country we met similar sons and daughters facing similar conflicts. Many facilities we found had long waiting lists - they would talk about three months and we had to find my mother something in weeks."
The Snows were fortunate. They found a home in Oxfordshire, widely regarded as one of the few specialist units in the country. A place became available and Joan remains there to this day. Mr Snow says he still has to deal with "terrible guilt".
"You have to take responsibility for taking someone out of their own home before they blow themselves up with the gas, or giving them the freedom to blow themselves up with the gas, and it's difficult.
"It's a very big step, taking someone's independence away from them. And what you know is that however good the home, it isn't a place you would want to be in yourself. You don't know what's going on inside of the mind of the victim. I really have no idea of what my mother is capable of knowing. I hope not very much."