The state has to file charges within 40 days of the arrest. Once charges are filed, a trial date is scheduled. However, the trial date can be changed if there are any continuances. If this person is on "no bond" status, then he will sit in jail until his trial is disposed of. He should consider filing a demand for speedy trial.
THESE COMMENTS ARE NOT LEGAL ADVICE. They are provided for informational purposes only. Actual legal advice can only be provided after consultation by an attorney licensed in your jurisdiction. Answering this question does not create an attorney-client relationship or otherwise require further consultation.
If speedy trial is not waived by his attorney, then the state has 90 days on misdemeanor and 175 days on a felony to bring them to trial. The state is allowed certain short extensions past that for good cause. If he is being held without bond, then he needs to talk to his public defender right away so that they can talk strategy for trial.
If this person is still in jail after 120 days, then the State has probably already filed formal charges. You need to find out if the Public Defender has "waived the right to a speedy trial." If not, then the State has approximately six months to bring the Defendant to trial. The Defendant always has the right to demand a speedy trial, which would require the State to bring the Defendant to trial within approximately 45 days. If the PD will not respond, the Defendant can write to the Judge and request a hearing for a Demand for a Speedy Trial. However, if a trial is not in the Defendant's best interest, then this person may stay in jail until the case can be resolved without a trial.