Disproportionate assets case

once charge sheet is submitted in the court by police, you will get court summons to attend court trial. the date and time will be mentioned on summons. accordingly your father has to attend. The matter will decide by the courts. 

he is already on bail, but he has been called on the chargesheet filing day by the investigating officer.... do we need to again reapply for bail.....

or there is no procedure for arrest again....

He will not be arrested again after charge sheet. He will continue to be on bail after charge sheet.

Starting of trial depends on the pendency in the trial court, and it differs from court to court. May begin immediately or may take some years also.

It is not necessary for you to file any discharge application. It is only optional and that too if you feel that there is no case made out against you in the charge sheet.

Copy of the charge sheet will be supplied to you by the police on their own, since it is mandatory to supply copy of charge sheet and statements of witnesses and other documents to the accused persons.

After charge sheet, charges are framed by the court and then evidence of witnesses will start.