He's always been a character and he's played to that persona very well. And once he gets on a roll, his mouth has always had a tendency to run away with him because he can't perform and pander to his own narcissism well at the same time. Result: word salad meanness. Gobbledygook.

And that's where you most easily see the performance vs the dementia.

The dementia is most evident in the clear decline of fine motor control over a short time span and more severe than usual age related decline, increase in paranoia and irritability, word salad episodes now include mixed up like-sounding words, drunken-like word slurs, and both of those have been demonstrably increasing as well. There's the raging and confusion. He's always been a racist and a misogynist, but he used to be a lot more sly about it. He doesn't seem able to control those impulses into a productive performance anymore.

There's just this disoriented lack of restraint around whatever lie of the moment he's on a tangent about.

Plus, he did used to love his blow back in the day. This is your brain. This is your brain after pickling it with drugs and leaving it on a shelf unused for 30+ years.
Any questions?

Too bad it's not still the 80s, yeah? Could Nancy Reagan have found a better poster boomer to keep kids off drugs? I think not. Just saying. Nobody sane and rational wants their last years on this earth to look like that. Could have changes the whole culture; there's no drug problem without willing customers.