From what I can see on the pictures, my guess is that the ribbon cable that goes between the screen and the rest of the device has been damaged.
This because there isn’t really anything that can protect it from tear when the protective case is broken and the ribbon is what holds it together.
What you could try regarding the case is to use super glue to put the broken pieces together, just be CARFUL to ONLY PUT GLUE on the places where it has CRACKED and not to get ANYTHING ELSEWHERE.
If you are lucky and not too aggressive when using the device this will probably work, otherwise, you could look after a broken device on the internet that has a good case.
You could also look if you have anyone where you live that have a 3D-printer and ask them to model and print a new case for you.
So I think you need a new ribbon cable then first try to glue the case together and if that dosen’t work, look for a replacement.
Hope this helped!
// eke0909 :D