If you can see the pulley (on the compressor) rotating as it should, that would indicate that the compressor *might* still be functioning within. If you can depress the valve core (in the low pressure fill valve located alongside the radiator cap) for a moment, you would want to have some freon escape. That would indicate that there is *some level* of a charge in the system.
With the engine running, and the AC selected to on (and calling for lots of cold air), you would want to feel a *major temp shift* in the pipes going to/from the high and low pressure service valves. If the *temp shift* between the 2 pipes does not exist, the compressor either is not *working* the freon as it should, or the freon charge is so low, there isn't enough in the system to get compressed (and create the warm pipe/cold pipe temp split desired). Then again, there very well could be a fault code (or codes) reported, that might say what was being sensed, that caused the compressor to stop making cold air.