Reset Options - iCloud email not accessible

The easiest solution if she still has the receipt for the iPhone would be to ask Apple to reset it completely. If that does not work then you'll have to try account recovery. You'll then reset the device yourself which is why if you can get Apple to do it, it solves both issues in one go.

Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Check the requirements and steps at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not detail what currently constitutes proof other than it “must include the product serial number, IMEI or MEID.” Apple may typically require the original receipt* issued by Apple or an Apple Authorized Reseller. If Apple resets the device this will give you access to the device but won't restore access to the account used to lock it. There is nothing that can be done to expedite an Activation Lock request.

*Apple recommends you "Keep your receipt after you buy an Apple device" --> Keep your receipt after you buy an Apple device - Apple Support

If you find you can’t sign in, reset your password, or receive verification codes, you can request account recovery (go to this document: How to use account recovery when you can’t reset your Apple Account password - Apple Support ) to regain access to your account. Account recovery might take a few days or longer, depending on the specific account information you can provide to verify your identity. One tip to using account recovery it to look for options in small blue letters beneath the normal log-in items if you cannot complete the requested information.

What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support