Hi,
I’m assuming that the LCD screen is OK, i.e. full display on entire screen and that the touchscreen (aka digitizer) is not responding on the left side. Is this correct?
If so then the touchscreen either has a loose connection to the systemboard due to the fall or it is faulty (you mentioned a small crack) and needs to be replaced as it cannot be repaired.
Here’s a link to the ifixit [[Topic:RCA RCT6077W2]] guides, which may be of some help in gaining access to the digitizer’s motherboard connection so that you can check if it is OK or not and also the screen if you need to replace it.
Here’s a link to just one [https://www.dhgate.com/product/wholesale-for-rca-rct6077w2-rct6077w22-voyager/395976003.html|supplier] for the replacement part.
It is shown only to give you an idea of the cost of the part and what it looks like. There are other suppliers online that may suit you better. Just search for ''RCA RCT6077W2 touchscreen'' to get results.
I suggest that you also bill your friend for the cost of the repair (and your time). After all this is their fault.