A demand for possession of an actual original will is suspicious on a number of levels. If your mother entrusted you with that possession, then giving it up may be a breach of her trust. In fact, based on the information disclosed it is not entirely clear that your brother is even entitled to see a copy of your mother's will. It may make a difference if you hold a court appointment as the executor of your mother's estate (as opposed to have been merely nominated for that duty in the will). Under the community property system, each member of the community owns an undivided one-half interest in the community property, and enjoys full legal power and authority to dispose of that half during life or after death, with the knowledge or consent of the other party to the community. For the precise advice you need for your case, a consultation with a local experienced elder law or estate planning attorney would best meet your needs. That attorney may be willing to intercede and respond to your brother's demands. Remember that the person with possession of the original will has the practical power to secretly destroy it and frustrate the wishes of the decedent.
Best wishes for an outcome you can accept, and please remember to designate a best answer.
This answer is offered as a public service for general information only and may not be relied upon as legal advice.
It is highly likely that your Dad is a beneficiary of your Mom's estate. As a beneficiary, your Dad has a right to see the will.
Your brother is your Dad's POA and acts in your Dad's stead to protect his financial and personal interests.
If he is asking to see the will, as the executor of your Mom's estate, you should provide only a COPY of the original executed Will as your brother needs it to transact your Dad's affairs.
I am assuming you are in probate? If yes, your brother - on behalf of your dad -- needs to abide by the rules and orders of the probate court - except for assets that pass directly to your Dad by operation of law.
If you have further questions or concerns, you may want to consult with a probate attorney.
AVVO or the Madera county bar association can provide attorney referrals.
You should never give an original Will to anyone other than the Court. In fact, in California the original Will is required to be lodged with the Court in the County where the decedent resided at the time of death. This is true whether a probate estate is opened or not. The Court then maintains the original forever and everyone else has a copy of the Will.
If I were you, I would lodge the original Will with the Court and provide your brother with a copy of the Will. If he wants to inspect the original Will, he can do so at the Court.
If you have a Trust, rather than a Will, then this does not apply.