Unlocking Apple devices after child's passing

See this article:

How to request access to a deceased family member’s Apple Account - Apple Support

Note that while Apple will provide access to the AppleID, there is no technical means to “override” or “unlock” a mobile device’s passcode.

Hopefully most … if not everything on the device will be sync’d and backed-up to iCloud so it’ll still be recoverable.

As for the device itself, it can only be erased and resused after Apple clears the activation lock as part of their decedent process.

Because of each country's customer information security policy, you should contact Apple support directly.

We understand … but without the device’s passcode, there truly is no means to access the device while it contains the data.

Apple can’t even do it.

However, the photos - and other data - is in all likelihood safely backed-up on her iCloud account - to which Apple can and will provide access.