Black screen repair, touchscreen still works and can hear sound.

The sudden stop on the floor is what broke it not the drop. Since the buttons don't work along with a black screen, I would think maybe a connector became loose. That would be something you might be able to fix. However, if it is something on the PCB like a cracked trace or a loose part, it might be very difficult to find and equally difficult to repair. Anytime a screen goes black, the first thing to do is to check the backlight by shining a bright light onto the screen to see if there is any video present. If there is video, along with the sound and touchscreen, then a good portion of the device is working, so it is likely a single point failure.

If it does not work and yo feel lucky, you might as well open it to see what you can see. I suspect a professional repair might be economically unfeasable.