Unlocking IPhone 6S
How to unlock phone, attempted to unlock, forgot passcode, now locked out, how to unlock?
iPhone 6s Plus, iOS 14
This is primarily a user-to-user support forum; other Apple users like you. The only way to unlock an iPhone that is passcode locked is to click on the following and use the instructions there: If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support
After you get it unlocked, have your wife use the following instructions (if she hadn't already): What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support