ipad locked former owner dead how can i use it?

Without the deceased person’s credentials needed to unlock the device, you can’t do anything at all. The exception would be if you have the original receipt and if you have proof that the device was left to you in a will or some other legal document. If you have those papers, you can take the device to an Apple Store and see if they will unlock the device for you.

This is Apple’s official stance on accessing the data on a deceased person’s device

How to request access to a deceased family member's Apple accounts - Apple Support

Good call. I forgot all about that kB article.