I think she's banking on people accepting whatever she says and not looking into it too closely.
Like Gigspanner and the people commenting on their supportive post.
Just saying, look I've been forced to share medical letters, will satisfy many people. They won't look further into why his illness (potentially a mild form of CBS, not confirmed terminal CBD) was diagnosed two years after the walk she's written about (2015 against 2013).
A lot of people would not only need this explaining to them, but would have to have someone go point by point with them through the book before they'd begin to accept something was amiss.
And even then a lot would still want to believe. It really is like a religion!