04 Stratus R/T

Problem: No start, no crank. Horn is dead. Dome light & door chim blinking/ringing very fast.

For starters, if this issue has already been ask/answered on another thread, plz link me to that thread. I tried searching 1st, but couldn't find anything similar to my specific symptoms.

So i was helping my brother install subs in his car. Haven't connected any wires yet, just layed in the power & RCA wires. Burring them under the trim and all that...
Removed his aftermarket radio (That i helped install a year ago) and noticed the electrical tape on the wires was coming off (Yes i shoulda done heat shrink & i kick myself now for NOT doing it) So i re-mushed the tape on the wires, while doing so I could hear his speakers making faint popping noises. I put the key in the AUX position, to turn on the radio, it worked fine, so while the radio was on i coiled up the wires & put the radio back into the mounting place. The radio cut out & ever since has not worked/turned on. Along with his car...

Symptoms: If a door is open, the dome light blinks VERY fast. 2-3 blinks/sec. IF the key is in, the door chime is equally as fast.
The horn doesn't work. Emergency flashers don't work. I try to turn the car over, no crank. Doesn't even click as if the battery is low.

What could I have possible shorted out with the freaking radio, that would cause an engine related electrical problem?????

 

So i checked EVERY fuse with a multimeter (Or at east every fuse i could find in the fuse box located in the engine bay and driver side panel in the dash) & all fuses were fine. I fixed up the wires for the radio with heat shrink to avoid this problem again.
I checked the batteries voltage & got ~12.5V. But for the hell of it, i jumped his battery with my car anyways.......& those symptoms went away & the engine turned over...
So for the moment, it seems his battery died &or went bad. So that'll get replaced. So the new question is; why would the radio shorting out kill the battery??

 

One of the wires in the harness (on mine it's the pink/yellow) is always hot. If it shorts to ground it kills the battery.