Biden maybe slow and thoughtful when he speaks but he is still able to talk coherently. He knows people and remembers where and when he is.
Trump is using slurring sounds for words he can't pronounce anymore. He forgets words.....but then his substitutes aren't coherent. He does this every time he talks.
His excuse for getting everyone's names and his locations wrong is it's a joke. Trump doesn't have a sense of humor. Unless someone is getting hurt or insulted, Trump doesn't really laugh.
When he makes a mistake, he doesn't know he made a mistake and doesn't correct it immediately. Maybe later he does a weird video with his eyes going in different directions about what happened. But he doesn't recognize his own verbal flubs.
Trump can't find the end of his sentences anymore. He just rambles around an idea, then the media fixes up the sound bite to make it seem like he actually had a complete thought. Sometimes he goes off on tangents that nobody understands. Like when he went off about the USS Gerald Ford, hydraulics and dissolving magnets. What???????
He forgets where he is. He can't remember people or the year. It's not that he's forgetting names, he's forgetting people, places and time spans.
He's forgetting where he is. He's forgetting what year it is. That's why he uses Obama's name over and over. He thinks he's in the past, maybe 2008 or 2012. That's why he can't remember his wife's name. He's forgotten who she is because he's back in 2004.
Notice his change in demeanor when he can't find a word. Right before it happens, his eyes go blank, his jaw gets slack, he looks confused and then stumbles over common words, and repeats the wrong word over and over. Like when he tried to say 3 years later. He said 3 years lady, lady, lady. He was trying to say later and became mentally disoriented and went blank.