Maybe he was trying to make a jumpseat?

In all seriousness...I don't give a sh!t what his reason was. He has the authority to declare an emergency for whatever he wants. That's why he gets paid the big bucks. Although, he also has to fill out the paperwork for declaring said emergency. And, if he's out to lunch...He'll be doing a tap dance in front of our friends at the FAA.

Having said all that...It's not the controller's responsibility to determine how much of an emergency, the A/C is in. If the capt. declared an emergency, they both should do whatever it takes to get the aircraft safely on the ground.