Developing an ASCOM driver is actual dirt simple. Especially the Safety Device.
Grab VS 2015 Community Edition
Grab the ASCOM Developer Components
There are some tutorials for ASCOM on their site:
http://ascom-standards.org/Developer/DriverImpl.htm
Alternatively you can probably find an existing Safety Device online and change that. I believe @Chris posted one a while back but I'm not sure if he posted the source. Actually I believe the source for his Boltwood Safety Device gets distributed with the driver if I'm not mistaken.
I guess that's a 2nd path you could take. Have some script that queries your device and writes a Boltwood formatted "one line" file. Then use Chris' Boltwood Safety Device to monitor that file.
If you do end up writing your own device I'd recommend RestSharp to handle the HTTP request and NewtonSoft's JSON Deserializer library (although it may be adequate to just do a string compare on the actual JSON rather than serializing it into an object)
Jared