NO< that is NOT TRUE. He called at 3:30 to say that his mom was not home yet.
And then an hour later, her brother texted and asked where she was. She replied Waterford. So I assume at that point they figured she was doing an errand, or something.
They realized she was late, running behind schedule, but were probably not truly upset until she missed going to work.
This time line from MSM says 6:30
http://www.examiner.com/article/timeline-surrounding-michelle-parker-s-disappearance