The emergency calls only message means that your phone can see a cell network but your device was refused registration on that network.
Since it's the law here in the US (and I imagine in most places around the world) that any cell phone needs to be allowed to call 911 in the event of an emergency no matter if there is a valid account in it, that is why you are seeing that message.
I would start by calling whichever cell provider you are using since they are the ones refusing your phone to register on their network.
He would be getting an SOS or SIM not provisioned message if it wasn't active. Maybe it's a pay-as-you go SIM. A friend of mine can still send SMS msgs if he's out of minutes but has no inbound or outbound calling.