Many thanks for the response. The appointments that are already there does not look like it's recurring. In addition, the calender is set to sync "All" and not a specific range of time. I did change from all to 3 Months synced and it's still not sync any existing appointments. For example, he has three all day appointments today but none of them synced to his smart phone while I create a new appointment and name it Test1 and it works just fine. It shows up fine on the smart phone after it's synced. I tried creating the Test1 in the past and it works. I tried creating Test2 in the future and it works. The only thing that's not working is those appointments that are already created. All the emails, contacts, and tasks showed up fine.
By the way, he does have Gmail and Charter email added to the smart phone along with his Microsoft Exchange email accounts. Those other two emails does not have anything in the calender. You mentioned about "check all the visible calendars in the app". How do I do that?