What?

https://support.apple.com/en-us/HT202303

Under Standard Data Protection photos, general drive storage and device back up are not end-to-end encrypted. Meaning that Apple has full access to reading and analyzing them.

Under Advanced Data Protection which is an opt-in feature available since iOS 16.2, you can have those files end-to-end encrypted.

End-to-end encryption makes the user responsible for keeping an encryption key safe, irreversibly losing their data if they lose the key. It’s not practical for the general population. I would guess its use is in low single digit percent of apple customers.

And this feature came out in December 2022. A bit over half a year ago. Unless your friend’s NDA was super short, I presume the conversation took place before it was released. Either your friend was bullshitting you under an NDA or he’s an idiot.