The description says he disappeared on September 7, 2003, but the thread title reads "9 Jul 2003." I assume this is because of the different ways "09/07/2003" can be read.
Apart from that, there's not much else to go on besides speculation.
James was last seen at a medical center. Was he seeking medical attention? Did he have any known health issues? Did he speak with a receptionist or even a doctor at the hospital? Did anyone else witness or even interact with him in the vicinity? That last one could be tough since Sep 7, 2003 was a Sunday so I don't know how many people would've been out at 7:00 am on a Sunday.
Also, how did he get to the hospital? Did he drive himself there? If so, did his car disappear along with him?
To complicate things, there's a
lot of open land
around the hospital and an airport! Now I don't think he could've flown out undetected, as security was still high in the years immediately following 9/11. But at the same time, I don't know how strict a county airport could be, so I guess we can't rule it out.
Far more likely, I think, is that his remains could be in all that open land. Were any searches ever done?