Facts
Fluid cant leak out if upside down.
Fade is when no mater how hard you pull the brakes don’t work, until you have had it you wont know what it is.
If the levers pull back to the bars and don’t do anything you either have no fluid in the system or air in the fluid, or someones pinched your pads.
Me I’d push the calliper off, the pads out, push the pots right back into the calliper [all 4] and dangle it from the bars.
Get a largish 200 ml syringe and a piece of plastic hose that fits snuggly over the bleed nipple.
Brake lever reservoir level.
Take off top cap.
open bleed nipple and pump all the fluid out. maybe catch it in something using tube mentioned above.
Now fill the syringe and tube with new DOT 5.1 fluid, make sure you purge air out [like the doctors do with a syringe on the tele.
Connect it to the bleed nipple and fill the system from the bottom till the reservoir is full, close the bleed nipple and don’t forget to roll your diaphragm in to the reservoir lid on and your brakes will be sorted.
Check for leaks at some stage.