Legal Question in Criminal Law in California

An indictment is an accusation by a prosecutor, not a decision by a court. Your son can't appeal because there is nothing yet to appeal from. He needs a defense attorney to represent him. If you and he can't afford one, the court will appoint one at public expense.

It's great that you already know of a potential weakness in the prosecutor's case, but that does not mean your son will win. And it certainly does not mean he can make the case go away now, which seems to be what you're hoping for.

A witness who has changed his story will probably be less credible as a result. But I can't tell how significant the changes are, and I don't know whether there are other witnesses and/or physical evidence that suggest your son is guilty.

As I said, your son needs a lawyer right away. Until he gets one, he shouldn't talk about the case at all with anyone -- including you. After all, you could be subpoenaed and ordered to testify about what he told you. So the less he tells you, the less you can be made to reveal later.

Good luck.