Make it available for us to transfer in game content

Sorry to hear you're having trouble. Although there is no way to transfer content or purchased items from one account to another if you accidentally redeem an item on the wrong account you can contact Xbox Support to see if they're able to make a switch. This must happen right away though

https://support.xbox.com

The data transfer cable is used to transfer the entire content of a harddrive from one HDD to another for the Xbox360

DLC, games and savefiles will just be available for download but will not be transferable through the transfercable. Savegames need to be saved to the cloud on the Xbox 360 before they are made available on the Xbox One the other content will just be available
as a marketplace download or from the ready to install list

Hello if you have Purchased these games then they will be available in your download history

Go to System > Account > Download History

also before you download your content make sure you transfer your content licenses

you can do this by going here

System > Account > License Transfer

Post back and let us know if this helped you

There is a way you could make it usable on his console, but it will require that you always be online when you want to use it.

If you do a license transfer on his console, then download the content, it'll be available for users on that console.

The new tool is available and I have a question. The website mentions that there is some content that won't transfer/migrate to the new region. My question however is about the content that does transfer. Does the purchase history transfer too? Will I be
able to download purchased games again (if available in the new region), even to a new console?

Or are all my purchases lost when I switch the region?