Logged in with parent account when I meant child

Hi, I downloaded Minecraft for iPad for my son today, he got some coins and stuff from the in-game store, then asked me to log in so it would sync to his other devices.

I'm an idiot anD without really thinking about it, I logged into MY microsoft account. Now I'm not sure how to get his coins and stuff to sync with his account, because logging out does nothing the coins and purchases seem tied to my account.

Is there any way to rectify this for him ?

:)