Inside it she had written:
To my dearest Humpty Dumpty, "Into your 40s now, gorgeous. Has all the hair gone now?!? "I love you and always will. So much." It was signed K xxxxxxx
Mr Pointon, from Mirfield, West Yorkshire, said: "It's something I'm slowly getting used to.
"She wrote them a couple of years before she died.
"There was this box under her bed which I wasn't allowed to open until after she died.
"There was a letter there for me which I opened on the day she died.
"There was a letter for a week after and she'd typed up her funeral plan.
"Getting the letters and cards has made losing her a little bit easier."
Dr Granger, who suffered from cancer, hit the headlines before her death after founding the "Hello My Name Is..." campaign, which called on NHS staff to introduce themselves by name to their patients.
After sharing the idea on Twitter, the couple were stunned to see it go viral, as supporters including Kylie Minogue, Jeremy Clarkson, Richard Branson, David Cameron and health secretary Jeremy Hunt endorsed the campaign.
Now the global initiative has been taken up in more than 20 countries and nearly half a million NHS staff sport "Hello My Name is... " badges.
Dr Granger discovered that she was suffering from cancer in 2011 after enduring terrible back pain while on holiday in California.
She was diagnosed with desmoplastic small round cell tumour (DSRCT) - a rare and aggressive form of sarcoma.
After surgery in 2013, Dr Granger developed sepsis and had to spend a long spell in hospital - where she realised many medical staff never introduced themselves by name.
A doctor and a patient
At the time, she said of her experience: "I'm a doctor, but also a terminally ill cancer patient.
"During a hospital stay in August 2013 with post-operative sepsis, I made the stark observation that many staff looking after me did not introduce themselves before delivering my care.
"It felt incredibly wrong that such a basic step in communication was missing.
"After ranting at my husband during one evening visiting time he encouraged me to 'stop whingeing and do something!'
"We decided to start a campaign, primarily using social media initially, to encourage and remind healthcare staff about the importance of introductions in healthcare.
"I firmly believe it is not just about common courtesy, but it runs much deeper.
"Introductions are about making a human connection between one human being who is suffering and vulnerable, and another human being who wishes to help.
"They begin therapeutic relationships and can instantly build trust in difficult circumstances.
"In my mind #hellomynameis is the first rung on the ladder to providing truly person-centred, compassionate care."
Alongside promoting her campaign, Dr Granger was secretly making sure that she could still celebrate her husband's birthday, even in death, writing cards when he wasn't about and hiding them under their bed.
The idea is similar to the plot of the 2007 film P.S I Love You, based on the book by Cecilia Ahern and starring Hilary Swank and Gerard Butler.
Mr Pointon has now taken a year long sabbatical from his job at Asda's head office to travel the world and promote the campaign.
Last year, he travelled to New Zealand, Tasmania and Australia where he delivered 21 talks in 25 days.
Dr Granger died on July 23, 2016, just three days after raising £250,000 for the Yorkshire Cancer Centre in Leeds - a challenge that was part of her bucket list.
In 2014 NHS England launched the "Kate Granger Awards for Compassionate Care" and again in 2015 she was awarded an MBE for her services to the NHS and improving care.
Speaking of her "Hello My Name Is" campaign, Mr Pointon said: "It has spread hugely across the world.
"It's so simple but it makes a huge difference."
