I don't have my iPad handy, but on my iPhone, there is a 'medical ID' feature, which if set up properly, can be used to access basic info.
On my phone, on the lock screen (where you type in the passcode), on the bottom right, there is a button on the bottom right that says 'emergency'. When you press it, it brings up a dialpad to dial an emergency number, and in the bottom right of that screen, in red, it says, 'Medical ID'. If set up, it lists the contact info. of parents, spouse, etc. if set up (and also other info. such as blood type, height, etc. in a true emergency).
Again, not sure if it is available on an iPad, but if so, may be worth a shot to get info. to contact family of the owner.