LG G5 wont turn on and get flashing red light
the red flashing light could be just due to a battery problem. Try this first https://thedroidguy.com/2016/09/fix-lg-g5-wont-turn-troubleshooting-guide-1060702 However it could very well be a problem with software. Most phones shutdown before the battery gets completely drained. I don't know if such chargers are available where you live, but technicians use chargers with prongs that connect to your battery to jumpstart it (You should not do this yourself) Try using a charged battery. If that does not work, you should take it to a repair centre.