Unfortunately, it doesn't look like the camera has the necessary BT protocols to support file transfers,
When in range of a conventional wifi router, I don't think the OP has any problems, it's when they are outside that range that I think the need arises to use the hotspot feature.
Since writing earlier I've had chance to look at what happens when a computer connects to the hotspot with no internet connection present. As you say, while the connection is possible, there is no mutual visibility between file systems even when the devices are configured in the same Homegroup ((Windows 7).
In that light, I'm not clear what danski ever saw that would have fulfilled the functional requirements of the FLIR software running on the phone without there being a separate wifi network in place. Maybe the FLIR app finds its way around that limitation somehow.
The only other option I can think of would be to buy a battery-powered wireless router which included a DHCP server that could be used to establish a LAN.
The only thing i can think of is his other device connects to the internet and somehow proxys the pics to his android (or somehow his android commands his device to do whatever its supposed to do) and since he doesn't have access to wifi hotspot, it hits a brick road.
Call up t-mobile and get the hotspot (was free for me on the 5gb plan)
Retrieving data ...