Only lawyers can meet during the investigation stage. You can call for advice if necessary. In addition, laws and regulations stipulate that family members cannot visit before the judgment. You can only entrust a lawyer to meet. Normal working hours can be reserved, and the time is different in different places.
The detention center will not inform the family members in advance. Family members will not be notified when they are released from the detention center, and they will not be notified one day in advance when they are released from the detention center. There is no such provision in the law. Just notify the guards one day in advance, and the guards can inform their families. Or the family members ask the detention center themselves. In general, the notice will be sent within 24 hours, unless it is impossible to notify, it will be delayed.