If the iPad disabled or Activation Locked, unless you can independently obtain assistance from the previous owner(the clearly, not being possible), the iPad is (and will remain) useless to you. Reseting the iPad will trigger an Activation Lock.
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 the original sales receipt showing the serial number), Apple may be prepared to assist - otherwise they and nobody here will be able to help you.
A close Family member or Executor, with the required supporting paperwork, can make application to Apple to be granted access to the Apple accounts of the deceased:
How to request access to a deceased family member's Apple accounts - Apple Support
You should note that if successful, this process will grant access to some information stored in iCloud - but will not, of itself, resolve access to the iPad.