Unless you are able to restart your iPad to a running state - and successfully enter your Passcode - you'll not be able to recover any data from the iPad.
iPadOS uses an encrypted filesystem. Successful entry of the iPad Passcode unlocks the Secure Enclave (this being the iPad's security chip) within which the only copy of the encryption keys - that are required to access and decrypt locally stored data - are stored.
If the incorrect passcode is entered too many times, the iPad will be disabled (as indicated), at which time the secure enclave is automatically erased. With the encryption keys erased, all locally stored data is permanently beyond reach.
The only possibility of recovery of locally stored data is reliant upon either:
a) data, such as photos, being synchronised with iCloud (requiring the AppleID and associated Password), or
b) access to a pre-existing iCloud or iTunes backup.
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.
Quite often, close family also have sufficient knowledge - and access to likely recovery paths - that access to the AppleID account of the deceased family member can be recovered. Having done so, it is then possible to release the Activation Lock that prevents reuse of an iPad/iPhone.
The following guidance is written from the perspective of the owner - but a family member will get the idea as they run through the process.
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If your device is Activation Locked, this help page will provide most of the information that you’ll need:
Activation Lock for iPhone, iPad, and iPod touch - Apple Support
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
Unless you AppleID account has not been fully/correctly configured, or has been seriously neglected, recovery of the AppleID and password should not be difficult.
More information about recovery of your AppleID:
If you forgot your Apple ID - Apple Support
More information about recovery of your AppleID password:
If you forgot your Apple ID password - Apple Support
