Linked parental account and now kid cannot unlock games without verifying age?

I don't really understand Roblox, but my 13yo brother wanted me to link parents account and ID to unlock maturity settings for his Roblox Studio games or something. I kept the birthdays as it is, set the restrictions to minimum allowed, but now he cannot play some games that he used to play without unlocking them by verifying his age??

He used to play them without issues and the parental account confirmed his age, so I'm dumbfounded why he now needs to verify anything again. Sadly, he doesn't have any ID and it's likely out of question anyway as it's locked behind 2-way verification on email he no longer has access to >_>

The way I see it is that his account is cooked. Is there a way to unlock these from parental account? Alternatively if I made him new account, would I be able to avoid the age verification headache?