Personally, until they stop using a 4-digit PIN to make changes then it'll be hard for the parents to think of a secure authentication mechanism. Security is only as strong as the weakest link, in this case it's only 4-digits. Until more people raise it with Apple support then it'll not change.
This. The 4-digit password is useless. I was stunned there wasn't an option even to make it 6 digits, but free form is best.