While I agree with a good deal of what you present here, this comment made me chuckle. Biden does this almost every time he speaks. It’s like being on pins and needles every time he opens his mouth.

That said, however, age is irrelevant. Mental health can deteriorate at any age from 0 to 123. Look at Morgan Freeman or Patrick Stewart, both 80 and all still going strong with sharp articulation and mental clarity.