You're really asking a philosophical question, not a legal one.
Criminal defendants are entitled to be treated consistently. That is why the government prosecutes crimes, and why judges make sentences.
If family members decided the sentence, one person might get a harsh sentence while another person convicted of the same crime under similar circumstances could receive very light punishment.
California law allows victims of crime and their families to give their input at sentencing, but the judge makes the decision.
This is a theoretical question, obviously. I would say no. It would not be appropriate for people who are biased against a defendant to decide the punishment. Revenge does not belong in a courtroom.
I do know and understand that you want to have a say, and this can be arranged by letting the prosecutor know you want to speak at sentencing or provide a letter to the judge stating your position as to the harm done and the punishment you feel would be appropriate. The judge will then know how you feel and will be able to take that into account. Most prosecutors will help you have a chance to make your points.
DISCLAIMER: I do not practice in CA. This answer to a short question is provided solely for general informational purposes and based on general legal principles and court practice. These may be somewhat different in your specific location. This answer does NOT constitute legal advice, create an attorney-client relationship, or constitute attorney advertising.
No. What if the victim has no family? The state prosecutes criminal laws on behalf of everyone, and the goal is to do so fairly, so that everyone is treated equally under the law. It's hard to enough to apply the law without discrimination and prejudice, that's why juries usually have 12 people on them, to balance things out.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.