That is a pity
I recall that they were not the most helpful of companies when I contacted them a few years ago. Sadly professional thermal camera kit like this is often challenging when it comes to support if you are not the original purchaser and many companies charge extra for replacement software, or ask you to take out a years support contract before helping. The pitfalls of buying professional thermal imaging kit that likely was very expensive and so support can be expensive/original purchaser only.
I have software for the other NEC AVIO professional cameras but some are for viewing saved images and others were expensive optional software to control the camera and stream images. I suspect the software you require was a chargeable product, even if included with the camera. That will make it very challenging to find for free on the internet
Even if you do, it may require registration to activate it. The was an SDK available for the camera, but, from memory, SDK's were also a chargeable package.
There was 3rd party software that controlled NEC AVIO cameras and NEC AVIO bought the rights to use it as their own. In its original version it was "WhiteBlue Software" and it contained modules that were individually purchased for different brands of camera. I have the NEC AVIO licenced version but sadly the company who wrote the software ceased supplying it some years ago and it may only be purchased from Solteccorp now.
This is the software i use. I cannot advise whether it has the required drivers for your camera though. You would have to ask Solteccorp or a NEC AVIO product agent. It is over £1000 for the licence and I do not think there is a DEMO version but you could ask. Many Demo versions did not control the camera.
https://daqlogsystems.co.uk/product/avio-infrec-analyser-ns9500-professional-software/Good Luck
Fraser
Sorry I cannot help more.