How can my brother get rid of his public defender?

Sorry it is not working out between your brother and his attorney. Unless the PD's office is representing a co-defendant or witness in the case, or formerly represented a co-defendant or witness, there is probably no conflict. The RI Public Defenders Office has a reputation of being good advocates for their clients. They are generally in court enough to know how judges/juries will react to various fact patterns; that means they often deliver bad news to their clients. Your brother generally has an absolute right to insist on a trial if he is not satisfied with a potential plea.

Forgive me, but I suspect that your brother has received news he does not like, probably a plea offer. Conveying such a plea offer to a client does not mean the client is being " sold out." Public defenders have to do this every day. But so do private attorneys, both retained and court appointed. All lawyers have an obligation to convey plea offers to clients. The court is not going to appoint a new attorney for your brother just because he does not like the lawyer now representing him. There has to be a complete breakdown in the attorney-client relationship. Your brother has a right to be represented by an attorney even if he cannot afford one. But if he cannot afford a lawyer, he does not get to choose who represents him. He also has a right to accept a plea offer, or reject it and proceed to trial. No one can force him to enter a plea. But his lawyer is going to tell him whether a plea is in his best interest. He can reject that advice, but he does so at his own risk. Based on what you have provided here, I do not see any conflict of interest. That's the best I can offer. Good luck to you and your family.

Nothing in your questions raises valid grounds for dismissing your public defender. Conflicts of interest can arise in multiple ways. The most common of which is for the public defender's office to represent two defendants, charged with the same crime, or in which one could become a witness against another. Nothing in your question raises a valid "conflict of interest" issue.