hmmmm, I suspect it will stop when you reboot... never while something that you aren't sure is going to finish
"Did you try turning it off and on again?" -IT Crowd
I was also having this problem. arcpy.Delete_management(GDB_path) would not remove my GDB, and left a weird folder behind. I attempted the while-loop approach (mentioned above), but that turned out to be an infinite loop, and I had to kill ArcMap to stop it. When I restarted ArcMap, the GDB hadn't been deleted. For fun, I tried running the original command again: arcpy.Delete_management(GDB_path). And it worked!
Restart to the rescue again!