I wanted to ask if there's a possibility to transfer his Minecraft worlds on the Xbox on the phone.
As far as I know, that does not work. Maybe there's something like a converter, but then there may be a few things missing. I have no example.
This is only possible through Minecraft Realms, which costs monthly and is a game-internal server where you can upload your world. https://www.minecraft.net/...de/realms/
In this world you can then access all devices that run on the "Bedrock" edition of Minecraft. https://minecraft.gamepedia.com/...ck_Edition
There's now a way to do this. See my answer ^^