Welcome to Apple Support Communities.
It's my understanding that your friend's touchscreen isn't working. I do have some suggestions that may help. First, follow the steps in this article: Get help with the display on your iPhone, iPad, or iPod touch
If that still doesn't help, make sure to have a current backup if possible: How to back up your iPhone, iPad, and iPod touch
Then follow this article to restore your friend's iPhone back to factory settings: Restore your iPhone, iPad, or iPod to factory settings Don't restore from a backup yet, set up as a new iPhone and see if you're still having issues with the touchscreen. This step will help determine if it's a hardware issue or software issue.
Let us know if this helps.
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