HELP!!! Cold Arowana - my heater broke while I was away! HELP!!!!!

I was away for two days & apparently my heater went on the skitz. The temp in my 200g tank dropped to what is registering 60degF. The water is cold to the touch, and my arowana is sunk, tail up, bobbing on the bottom of the tank... He's barely breathing and moves minimally when the water is agitated. I put in two back up heaters, and have my literal space heater blowing on the tank hoping to heat is slowly, but efficiently.

I changed out 20 gallons of water with warm water to hopefully give it some heat without shock.

All water parameters are within range.

Would the drop in water temp cause this reaction?

I dont want to stress him without cause, but PLEASE what can anyone recommend?? I have had this fish for 4 yrs - three apartments - and raised him out from a baby!!! He is a monster and my best friend and I dont want to loose him!!!

Is it best to let it and him be with the heat running, or do you think to push him a little? He's in front of the heater now, but I find that when I tapped him a bit (moving the tank around) he tried to level out but just doesnt have the energy.... its like his head is too heavy for the rest of his body. I dont want to stress him, but is it possible it may help getting him moving?

his eyes have a white film, but otherwise his slime coat and color are fine...

thank you... Ugh... im so frantic!!!

so the tank is up approx 2degF somewhere about 62degF now... The aro has been trying to move a bit on his own here and there [I think a good sign], but he also seems to be shedding his slime coat a bit now, esp from his tail? Is this a normal response?

I've only been eying the tank from across the room... no further steps taken other than dimming the lights and closing the curtains...