LG G5 Won't Start // Flashes 0% Charge

[AC Question]

Hiya! Hoping to post on here to get some answers;
My LG G5 just will not start up at all. I've tried hard resets, I've removed the battery and put it back in, I've replaced the cable, literally tried everything I could find online and yet this problem still persists.

If I press the power button when it's not connected to a cable, it flashes a very brief image instructing me to connect it to a charger. Once I do that, however, it flashes with a 0% charge image, a 'buffering' circle, and then remains black for about 4 seconds before doing it again and falling black again. When it is black, it flashes red about 5-8 times.

I've left it on charge overnight in the hope that it'd be fine in the morning but that didn't help either.

At this point I'd just like to know if there's a way to fix this at home? Or do I need to see a specialist. I'm awaiting an important phone call from the hospital so this couldn't have come at a worse time.

 

[Rukbat]

The battery could be dead (the "proper" misuse can kill a lithium battery in less than 6 months), but unless you're familiar with battery testing with a load (an almost dead battery with no load can show pretty close to the same voltage as that battery fully charged), I'd bring it to a repair shop.