Why Jerry didn't take the stand

Elizabeth Hewitt has an article in Slate about the Sandusky trial:

Part way through the two-week sex abuse trial of Jerry Sandusky, the former Penn State football coach’s adopted son came to police with details of how his father had abused him from the age of eight, according to a police interview tape obtained by NBC News.
In the interview, which was recorded while the trial was going on, Matt Sandusky, who was adopted by Jerry Sandusky at the age of eighteen, recalled instances when his father molested him in the shower and in bed. He claims that the incidents began in the late 1980s, a decade before the allegations Jerry Sandusky faced in court.
Although Matt Sandusky told police he couldn’t remember if he engaged in any sex acts, he said that as a result of his father’s behavior he had tried to escape and, at one point, attempted suicide. "I know that I really wanted to die at that point in time," he said during the 29-minute-long recording.
Matt Sandusky had steadfastly supported his father’s defense, even helping to carry boxes into the courtroom and attending the first day of trial with his family. After hearing the testimony of the accuser known as Victim Number Four, he went to police to reverse the account he had told investigators, according to the Associated Press. In the interview, he told police he came forward "for my family" and to "right the wrong" of lying to the grand jury.
Matt Sandusky’s testimony to police was said to be a "complete shock" to his father. Jerry Sandusky’s defense said they decided to keep their client off the stand after learning about Matt Sandusky’s testimony, as the prosecution would have called him as a rebuttal witness.
The tape is real, Matt Sandusky’s attorneys confirmed in a statement, saying the interview "illustrates that he made the difficult decision to come forward and tell the painful truth to investigators despite extraordinary pressure to support his father".

Rico says who knows what's 'real' in this case, except that Jerry Sandusky certainly is a lower lifeform than the slime molds, and will undoubtedly die in jail, whether by getting old or getting gang-raped by the other inmates...