Hi Sibro,
His battery is dead flat so can't turn the laptop on even with the charger plugged in so installing software at this stage isn't going to happen.
That sounds like a hardware problem. The battery isn't controlled by the OS, so if the device is powered off, the battery should be able to take a charge without any drain/usage occurring.
Subsequently, the device should be able to post/boot from the charge the battery has (or at least from the steady power input when connected directly to the charger) since the initial BIOS/UEFI phase happens before the OS comes into play.
It's possible the battery of the device is defective, or the charger isn't functioning properly.