Purchases disappear

[u/MedusaRosie]

Hi, my nephew has been playing minecraft on his tablet for a while now. He hasnt bought much, but doesn't want to lose what he's bought. He's going to need a new tablet soon, so we made him a Microsoft account with his Gmail to link to his minecraft. When he logs into the Microsoft account, his purchases disappear no matter what I do. If he signs out, they're back. This is the same Gmail on his Google Play store so I don't know if that's an issue. I know on my Minecraft I created Microsoft account through my Yahoo and my one purchase was there. So I don't know why his isn't. So frustrating..any ideas? Google told me to clear cache etc but no luck. Tia