How to know if a iPhone 5 doesn't work or just has a dead LCD?

How do I know if a iPhone 5 doesn't work or just has a dead LCD?
A friend of mine gave me an iPhone 5 he had that has a broken screen, he was able to use it since touchscreen was responsive. However last week his phone just did't turn on and he gave it to me as a gift.
Is there a way to know if the phone is totally dead or if the LCD died.
(For example, Android phones vibrate even when the LCD is dead and most have a boot animation which you can hear)
Any ideas, comments etc is appreciated. I don't want to buy an LCD for no reason.
I have never owned an iPhone, but if I recall, the iPhone does not have a boot animation or sound that would confirm that the phone did turn on.

Hold the power button and the home button at the same time for about 45 seconds, if it works and has a battery charge you should see the apple logo or at least the screen back light turn on. Try and do this in a dark room.

Just replace the screen

Plug it in (while in vibrate mode). If it vibrates, its not dead. If it doesn't vibrate… Sorry: l