Impossible to reset Apple ID and password on mum’s iPad. Please help

Presumably you are being prompted for your AppleID credentials - so as to satisfy the Activation Lock. You will require the AppleID an associated password that was last used to successfully activate the device - which, for the bona-fide owner, should be straightforward.

Here are the Apple support pages that outline the Activation Lock - and the only mechanisms by which it can be satisfied:

Activation Lock for iPhone, iPad, and iPod touch - Apple Support

Turn off Activation Lock – Apple Support

As you will discover, unless you are the owner of the AppleID that was last used to activate the device, you’ll not be able to defeat or bypass the Activation Lock. With documentary evidence that you are the original owner (such as sales receipt showing the serial number), Apple may be prepared to assist - otherwise they and nobody here will be able to help you.

If you have the necessary documentation, Apple have introduced a new portal though which you may be able to request release of an Activation Lock:

How to remove Activation Lock - Apple Support & start an Activation Lock support request.

However, recovery of the AppleID credentials should be possible…

If you have forgotten your AppleID or associated password, these can be recovered here:

https://iforgot.apple.com/

To recover your credentials, you’ll need access to any one of the following:

• Your primary email address mailbox that corresponds with your AppleID
• Any of the secondary/recovery email addresses that should be configured for your AppleID account
• Any of the trusted telephone numbers (fixed line or Cellular/Mobile) that are associated with your AppleID

More information about recovery of your AppleID and associated Password:

If you forgot your Apple ID - Apple Support

If you forgot your Apple ID password - Apple Support

Consider that an AppleID account is intended to be used for life. If you need to change the primary email address that identifies your account, or your secondary (recovery) email addresses or trusted telephone numbers, you simply need to update your AppleID account as necessary.

Change your Apple ID - Apple Support

Change your Apple ID password - Apple Support

What to do after you change your Apple ID or password - Apple Support

Change, add, or remove Apple ID payment methods - Apple Support

Few of us will have the luxury of forever keeping the same email addresses or telephone numbers - sometimes these needing to be changed for a variety of reasons. However, updating our AppleID account, maintaining access to our devices, data and purchases is easy and relatively straightforward - accommodating life’s many changes as they occur. 

Neglecting to keep your AppleID account accessible has consequences - including potential loss of access to devices and the AppleID account.

Dementia is a cruel disease. Your concern and evident frustration is fully understandable; many have been where you are now.

Unfortunately, creating a new AppleID is unlikely to address your issue - as without the AppleID credentials that were last used to successfully activate the iPad, the associated Activation Lock cannot be disabled. Unless this is resolved, the iPad is (and will remain) useless. Without the receipt or proof of ownership acceptable to Apple, they will not assist.

I can only, as requested, wish you luck.

Tip: When (one way or another) you resolve this problem, ensure that you have configured yourself as a Recovery Contact for your Mother's AppleID account.

Set up an account recovery contact - Apple Support

-LP