Legal Question in Criminal Law in California

Anything lesser and related that doesn't carry 290 registration is possible, but the big question is: Is the DA willing to offer that and why?

Without knowing any of the facts of the case (number of images, static vs video, the content [posed vs extremely graphic, exceedily young, etc]), it's impossible to gauge this case. Also - his attorney should probably be getting some sort of psychosexual evaluation (akin to a 288.1 report) to assess your son and any risk of future deviance.

Your son cannot plead to a lesser offense unless the D.A. is willing to make a deal allowing such a plea. It's not something he can do unilaterally. The D.A. is not required to offer a deal at all, let alone to offer one that meets criteria chosen by the defendant.

The background you describe may make the D.A. more willing to offer your son a deal than he would otherwise be, but it's not the only factor that matters. The facts surrounding the current charges matter, too. So will any additional evidence the government finds as it investigates the case.

Your son's public defender knows more about his circumstances than any of us do. She will be able to assess his chances of getting a deal, and she will know how to negotiate the best deal available to your son under the circumstances.