First off...that thing is ancient and needs to go. Parts are obsolete on it.
The lever is the emergency lever. Its in the off position.
Here's the skinny on drum brakes...If it was parked with the slightest pressure on the hitch, The shoes have formed a chemical bond to the hub. You must beat and bang around the hub to break that bond loose. It will still be a booger to remove. Check behind the Hub also...look for a slotted hole. That's where you can back the shoes off.
To be honest, its looks like a very old unit. (trailer) As much work and time that your gonna put into this, I'd suggest getting a new actuator and axles with Disc Brakes. You have my number...