Can ATC handle a flight as emergency although the pilots have not declared an emergency?
In the US, a controller has the authority to treat any situation as an emergency, and they do.  I have had controllers &quot;declare&quot; an emergency multiple times, even when I thought I did not have an emergency.
There are some advantages to the controller.  His work gets shed to others, and his supervisor is at his side to assist.
At one point, after ice, delays and trying to get into a DC airport close to the Christmas holiday, I declared &quot;minimum fuel&quot; which I didn't consider an emergency.  I just wanted to let the controller know that if they vectored me towards West Virginia again, I would be landing close to or at reserves.  The weather at the destination was far better than the ice I have been flying through at 13,000, but I wanted to avoid plunking down at Martinsburg, away from my destination to buy another load of fuel.
Immediately I got handed off to a Dulles controller, whose radar had better coverage than Baltimore Approach who handled approaches normally for my destination.  I got kid glove treatment, and did not get further delays, and landed at my destination without any incident.  After the paperwork, I dipped the tanks, and figured I still had about 27 minutes more fuel than my minimums for IFR night flight with a diversion to better weather.
Similarly, having gear problems almost always gets an &quot;emergency&quot; status.
I will say one thing, when I was dealing with a cockpit fire, and the controller kept asking again and again the same questions it was distracting, but they are trying to get their job done the best as they can, just as the pilot is.  In my case, I just stopped answering lower priority questions.  In the case of the cockpit fire, I killed the master switch (at night), and another pilot in the back brought ATC up on his handheld radio.  Up front we dealt with the fire, and delegated the communications to a guy in back.
So in application to the LNI610 and other situations, it makes sense that the pilots exercise their ability to tell a controller to &quot;standby.&quot;  It works some of the time.
I am not as familiar with the US Controllers Handbook as I have been in the past, but I am confident that the controllers have authority to declare an emergency.  But keep in mind that they are products of their environment, just as pilots are, and they have training, objectives, experiences and organizational expectations which change and vary.