just to add to the question, the same ip address shows up every time i talk to him on skype and he’s the only person i know that lives in that city and state
The simple answer is that there is no way for you to know. In a commonly recognized scenario that most people might recognize, consider the use of PCAnywhere or even basic Remote Desktop. Discussions of how ISPs assign addresses and how technologies such as used by Skype or IP phone services quickly make things far more complicated.
He could also be VPNed into his office here in the US in which the IP Address that Skype shows could be from his company in the US.