Adult protective services/DHHS - how long does an investigation take?

So a friend of mine works for a place that does in home care for the elderly and disabled. Sometimes they also drive the patient to doctor appointments as well.

A couple weeks ago, my friend was driving a small bus with several patients and employees on board to the grocery store. After they went in the store, one of the patients wandered away from the group and had to be located. It took approximately 30-45 minutes to locate the patient, once they did, he was found to be perfectly fine and showed no signs of upset or fear or anything like that. The incident was reported to the supervisors of the employees, who were required by company policy to call DHHS/APS.

My friend and 2 of his co-workers were placed on paid leave while DHHS completes their investigation. He could lose his job over this, depending on the results of the investigation.

Can anyone tell me how long and investigation with APS usually takes? It’s been nearly 2 weeks now and the suspense is driving us all crazy. At this point, he doesn’t even care about his job, he just wants to know what’s going on. If anyone has any insight into this kind of situation it would be much appreciated! Thank you!