iPhone screen colors are dark, screen flickering after being dropped

My brother’s iPhone 5c was dropped from a high shelf and now the colors are dark and the screen flickers. I can see faint outlines of apps on the home screen sometimes in other apps. I opened the phone and unplugged the screen and plugged it back in, and the problem is still there. I noticed that the glass seems to be separating from the rest of the screen, and the battery (which was replaced a few years ago) fell out, it was just held in place with some double-sided tape. Do I need to replace the screen? Or would this be possible to fix, ideally without spending any money?