The special prosecutor who spared Biden from a criminal case instead took aim at his age, mental fitness and fuzzy memory. That went too far, according to former special counsel prosecutor Andrew Weissmann. “There is a part of this report that is really hard to stomach,” Weissmann told Lawrence O’Donnell during an appearance on MSNBC’s “The Last Word”. “A job of the prosecutor and whether you are a special counsel or not, is to decide whether there is sufficient proof to prosecute. That’s it. And if there is, you can say that. If there isn’t, then you say that. Want more breaking political new…