" just stuttering and not responding." kinda tells me that he must have the TX on or why would he be expecting a response. Let's not treat him like he's stupid.

I agree that he MAY be using the wrong modulation type or be too close though. Having the TX about 4 feet away should be more than adequate and double check both RX and TX are in PCM or PPM mode.
Also make sure RX antenna is fully extended and mounted well.