One assumes, as this is accessed via the AS site that this is legit - why would you think it wasn't? I am resaonable certain that the Alzheimer's Society wouldn't link to it unless they had checked it out. It isn't possible for a link to appear on the News page without the society's permission.
Not sure. I was doubtful about the first part, and that was before I had read the messages. It just seemed unrealistic that he was sitting in his chair, totally unresponsive and uninterested in the mail, then he was out 'posting' letters.
The second part was more credible, the arguments rang true, but unfortunately the sound was poor, kept stopping and starting, so I couldn't really judge.