President Trump's episodes of confusion, erratic behavior (even for him) and apparent loss of mental focus (and I use the term "focus" very loosely) seem to become more frequent under stress. It's the same pattern I saw with a friend of the family who suffers from early onset frontal lobe dementia. I notice other troubling similarities as well: incoherent speech with lots of repetitions, a shrinking vocabulary, and frequent failure to remember specific nouns and people's names. He further shows an inability to let things go, uncontrollable emotional outbursts, paranoia, projection (noting in others the problems you have yourself, often falsely accusing others of it) and "reverse projection" (taking strong influence from others and being easily persuaded because your own mind is weak).
I don't know how much if this is typical for the disease, but it's a very close fit with the one case I have experienced up close and personal. If President* Trump is losing his mind while also trying to hide it, we may be in even deeper trouble than we thought. Phrases like "he is out of his mind" or "he doesn't know what he is doing" may be true in a very literal sense. It wouldn't excuse anything, but it would explain a lot, and it would shift a lot more of the blame onto his inner circle for providing cover and being his enablers.