no passcode

Go ahead and try to wipe and restore it.

If she never set up an activation-lock, the iPad will be problem-free. If she did set up the lock, you will probably have to find the receipt. But Apple Store visit may yield soothing.

 

Apple cannot and will not "unlock" - they will not give you access to someone else's information. They can help you erase the iPad (which removes the passcode lock) so that you can use it "clean." To erase, see https://support.apple.com/HT204306

If you just want the iPad unlocked so you can use it for your own purposes - the question is whether the iPad is single-locked (just a passcode lock) or if it's double-locked (passcode lock plus Find My iPhone Activation Lock). Here's more about Activation Lock: https://support.apple.com/HT201365

If you also want the information on the iPad - no way to get that, unless your relative kept a backup in iCloud or iTunes that you can access (possessing Apple ID password for the iCloud account). If there's a backup, you can erase the iPad to remove the passcode lock, then restore from the backup.

 

Reach out to Apple Support by phone. Make sure to have the death certificate available. You may have to send it to them. Provide them information so they can link the death certificate to the iPad Mini and ask for their help in wiping the system so it can be re-used. Be nice and you may get lucky.

 

If you're asked for the passcode, then you haven't put the thing in Recovery Mode

Connect to computer
Hold power button and home button until you see the "connect to iTunes" screen (iTunes logo and Lightning cable).
Release buttons
On computer screen, you'll be given option to Update or Restore iPad. Choose "Restore"

 

Try the combination lock code from any open briefcase. On the assumption that birthdays are too obvious, try military or work staff numbers. Beware max permitted attempts.