I believe that he is suffering from some form of dementia. What ever it is it is progressive as he seems to be getting wackier and making comments like this more frequently.
When someone gets that way it is almost better that they pass quicker rather than live a demented state for years.
But I could be wrong and he just got a different set of pills that give him more energy, therefore allowing him to up frequency of his insane comments.
When Carter was in office, I had a relative who worked in D.C. and he claimed that the real Jimmy Carter had been replaced with a double. Sounds far-fetched but...