I and many others have been concerned for some times that 72 year old John McCain is showing signs of his age and perhaps the consequences of his time as a POW. As a psychotherapist, I am aware that most POWs return with some version of PTSD. Back in McCain's time in prison, it wasn't common to ask for help when one returned. Even if he had asked for help, there weren't a lot of treatments available.
So today, when John McCain addressed an audience as "my fellow prisoners" you had to think your concerns were well founded. Something is very, very wrong here. The most common expressions he says are "my friends" and "my fellow Americans." "My fellow prisoners" would not be something that would come naturally to him, especially as it was unlikely that he gave speeches to his fellow prisoners in Vietnam, as much if not all of the time they were kept separate from each other.
This indicates to me one of two things: either McCain is having flashbacks, which could explain his erratic behavior lately as well as his hostility to Barack who he sees as the enemy, or that he has early stages of dementia.
This man is not a safe choice for president, especially with his second in command. This needs further investigation - we need to see his medical records for more than just an hour.