Legal Question in Civil Litigation in California

No. You cannot demand to see privileged documents. If he disclosed a privileged document to you without the client consent, that client may have a claim against the attorney (probably just an ethical one though.)

I agree with Ms. Karila, though I would need more details before I could offer any concrete guidance.

Note that not all communication between an attorney and his client is privileged. Your belief that this one is privileged may be incorrect. Even if the privilege would normally apply, the client may have waived it.

What you are talking about is waiver of the privilege. That is a very complicated subject and the outcome of a dispute over whether certain conduct waived the attorney/client privilege and to what extent is specific to each case. It would have to be determined on the basis of a detailed review of what was disclosed and the exact circumstances of the disclosure, along with an analysis of the exact legal precedents that apply to those specific detailed facts. So you can demand whatever you like, but whether you will get it or not is a whole other matter. You can count on a big fight about it no matter what, unless the attorney doesn't think the additional emails you demand are privileged (not every communication from a client to an attorney is privileged), and in any case you will never get a reliable prediction of the outcome via the internet.

I agree with everything previously said and would only add that if you demand these documents a judge, not you or the other attorney, will likely have the final word on the subject.