Glad someone pointed out that invoking the 25th. Amendment is not an easy process.
Invoking the 25th amendment gets a lot harder when the VP is also brain dead.
2/3 of both Houses of Congress, which means, even if every Republican voted to remove Biden, he stays, unless 70ish Democrat Representatives, and 18 Democrat Senators, also voted to remove him.
That is a very large number, especially given that, if the vote is at all close, it will be political suicide for many of those Democrats to join with all(?) Republicans to remove a Democrat POTUS.
If they were to try the 25th Amendment, I expect that they would have to plead some intervening event that suddenly, and sadly, compels loyal Democrats to vote Joe out. If we get a spate of stories that it has just been discovered that Joe has had a series of strokes recently, then the 25th Amendment is in play.