Here is what was actually said.

But Hur added that the evidence “does not establish Mr. Biden’s guilt beyond a reasonable doubt.”

“We have also considered that, at trial, Mr. Biden would likely present himself to a jury, as he did during our interview of him, as a sympathetic, well-meaning, elderly man with a poor memory,” the special counsel said.

“We conclude that no criminal charges are warranted in this matter,” the report said. “We reach the same conclusion even if Department of Justice policy did not foreclose criminal charges against a sitting president.”

In other words the first consideration was that the evidence does not establish guilt beyond a reasonable doubt. And he is a sympathetic old man with a poor memory. It doesn’t say he’s mentally unfit or unfit to stand trial.