It just seems one of them has more mental health problems than the other.

Yes. The one who:

has Confused Nikki Haley for Nancy Pelosi

thinks that Obama is the current president

thinks he beat both Bush and Obama in elections

has on multiple occasions bragged about acing a “difficult” cognitive tests that doctors say are simple for people with normal function. As one doctor put it, “It’s a very, very low bar for somebody who carries the nuclear launch codes in their pocket to pass and certainly nothing to brag about.”

And this is just sample of the recent stuff. Would you like to go back to the time period where he was suggesting that people inject bleach to protect themselves from COVID?