You have a very common problem, which, regrettably, is not well provided for by the law (in Virgnia, or anywhere else in the USA). The problem is that the trustee of a trust has a legal duty to inform beneficiaries of their rights in the trust and to account for the trust's ongoing financial status. VA Code § 64.2-775.
However, there is no law that requires the trustee to notify persons who are not beneficiaries. Consequently, when a trust becomes irrevocable at the death of the grantor (your father), the trustee could, if he or she is deviously inclined, simply tell one or more beneficiaries nothing -- and, take a chance that the beneficiary doesn't petition the court for an accounting of the trust.
And, that's effectively where you're at in the chain of events. If you are a beneficiary, and your brother won't send you a copy of the trust instrument, then your only recourse is to petition the court for an accounting, based upon your "information and belief" that you are a beneficiary of the trust, and that your brother is concealing this fact in order to misappropriate the trust property.
My approach would be to send your brother a letter, certified mail, return receipt required, ask him for a copy of the trust instrument, and state that if he does not provide a copy to you, that you will be forced to assume that he is attempting to conceal your status as a trust beneficiary, and you will petition the court to force him to disclose the trust instrument to you and the court for review.
In short, this is "hardball," because if you're not a beneficiary, then your relationship with your brother is probably finished. That's not to say that there's anything wrong with advancing your rights. But, where family is concerned, some people need to consider the emotional and financial issues together. I'm merely mentioning this to be thorough.
I hope I've answered your question. Please let me know if you require further clarification. And, please provide a positive feedback rating for my answer (click 3, 4 or 5 stars) -- otherwise, I receive nothing for my efforts in your behalf.
Thanks again for using Justanswer!