Can you help unblock my mother-in-law's iPad account?

So . About five years ago I gave her an iPad, I think an ipad 3. it still works well. That's why I love apple products.

But! She locked her account. I'm trying to get it back up. I know the passcode, her e-mail and password, but there is also a phone number! Unfortunately my mother-in-law doesn't remember it. Not at all. Of course she thinks it's my fault =)

to lay one's own fault at somebody else's door.

I would be glad if you could help me. I want to look like a hero in her eyes (if possible). I know it's all strict security rules, but is there any steps I can take?

Once again, I know the passcode and password to her email (I made them up myself 5 years ago) but the phone number is unknown to me.

[Re-Titled by Moderator]