Strange number in iPhone emergency contacts

I was updating my phone today and noticed an unknown number under “son” in my emergency contacts.

It’s a real number (I looked up the number in WhatsApp and it’s connected to an account), but I

definitely never added it to emergency contacts and I don’t even have a son!

It was very creepy so I’ve blocked the number now and changed my iCloud passcode just in case, but does anyone know how that appeared there?

Has someone hacked my iCloud account?

[Re-Titled by Moderator]