Another thought . .
What does your brother's Public Defender have to say about the situation? Surely your brother called him on it?
Is your brother the only one who overheard these "remarks"? What were they?
Everthing here depends on what was said and in what context it was said in. PD's are often young - inexperienced - and working at the job for experience in procedure for when they open their private practice or apply to a firm as an associate. They lose a significant number of their cases at trial and encourage clients to plead out some that shouldn't be. Wealthy defendants do not beg Public Defenders to quit the office and defend them in homicide cases for $800 an hour based on the PD's mind-boggling, ultra-successful trial record. The Constitution guarantees the right to counsel: not good counsel or excellent counsel: just adequate counsel.
If in fact, the Public Defender does not like your brother - or his charges - or the case - and it happens - he might have expressed any number of things to the Prosecutor off the record - that happens too. And they are not stupid. For instance: if a client is forcing a PD to try a case that the PD knows cannot be won; and there have been plea offers rejected by the client: plea offers that include sentences that both the PD and the Prosecutor know are lighter than what will be handed down by a jury or a judge, it would not be unheard of for the PD to refer to his client as "uncooperative" - perhaps using much stronger language. A trial win for a PD in a major felony case would be a big feather in his or her cap regardless of whether the client is actually innocent. But it's not completely impossible that your brother has been assigned someone who only wants to win if he honestly believes in the innocence of the client - someone who will very probably end up handling real estate closings.
If your brother really feels he is being inadequately represented, he can instruct his Public Defender to petition the court for substitution of counsel. If the attorney refuses to do it, your brother can ask to address the court; stand up and explain the situation to the judge. If he is denied the substitution, he will have created potential grounds for appeal. I'm guessing that since your brother has not accepted a plea and has been sitting in jail for over a year, he is either innocent or thinks he can prove he is innocent. Did the "co-defendant's" plea include his agreement to testify against your brother? In most states, that indicates that the prosecution has other independent testimony - possibly from some fine upstanding citizen - that will confirm - corroborate - the co-defendant's testimony.
HOWEVER, on the other side of the scale: if your brother starts some big broo-ha-ha that the Georgia court views as a smokescreen to prolong what it believes (privately, of course) is inevitable - in a case with overwhelming evidence against him - he will not endear himself to either his PD or the court. This especially true if pre-trial motions have closed and a trial date has been set.
