Hi LarryTPost,
Welcome to the Apple Support Communities!
I understand that after resetting a friends iPhone from your computer, their iPhone seems to be attached to your accounts. It sounds like their iPhone may have been restored from one of your device backups when you connected it to your computer.
If this is accurate and your friends iPhone was restored from one of your device backups, their iPhone would include all of your data.
At this point, I advise restoring the iPhone again and setting it up as a new iPhone or restoring it from an iCloud backup using your friends Apple ID (if they had a backup prior to connecting to your computer).
Restore your iPhone, iPad, or iPod touch from a backup - Apple Support
Was there an issue with the iPhone before it was connected to your computer? What prompted that action? Does your friend have their own Apple ID?
Cheers!