“Can the prosecutor keep on refilling criminal cases? My brother got arrested 2 times in 6 months, for domestic violence with the same person, he has court again in 2 weeks …”
A misdemeanor case can only be filed once; if it is dismissed, then penal code 1387 bars any re-filing.
A felony matter, by contrast, can generally be re-filed such that the DA gets a second bite at the apple – again, penal code 1387.
Please note that the prosecution can file separate cases against your brother with the same victim, as long as the incidents are not part of the same occurrence (penal code 654).
In a felony case, your brother has the following time rights: (1) 10 court days from the time he is arraigned on the felony complaint to be brought to preliminary hearing; (2) preliminary hearing must take place within 60 calendar days from the time he is arraigned on the felony complaint; (3) prosecutor has 15 days from the time your brother is held to answer at preliminary hearing to file the information (formal charging document); and (4) bro must be brought to trial within 60 days from the date he is arraigned on the information. The DA can often get your brother all the way to the 60th day even if the alleged victim has been unavailable the whole time, including at preliminary hearing, via prop 115 hearsay testimony.
In a misdemeanor filing, your brother would have the right to a trial within 45 days from the time he is arraigned, assuming he is out of custody and decides to enter a plea of some sort; if your bro is in custody at the time of arraignment and plea, he is entitled to a 30 day trial window.
I hope those time rights help you consider the possibilities.