iPhone 6s display black but showing up in iTunes.

Ok this is my sisters old iPhone 6s and she’s messed it up pretty bad. She stood on a wall and threw it onto grass, the screen popped out went black.

I ordered a new screen and weirdly replacing it didn't not fix it, its not the backlight the screen si completely off. there are no system sounds or vibrations, but ti shows up in finder on my Mac. I restored it and it failed, error 9. This was the first time it lit up (it showed the recovery screen). I tried to restore again and it worked. The phone is now activated and in normal mode and detected by my computer. There are still not sounds, vibrations or screen.

I have changed the screen, battery and dock connector and that didn’t fix it. I DISCONNECTED THE BATTERY FIRST WITH EVERY REPAIR.

Any ideas what’s wrong with it? :)