Unsubscribe from Nintendo Network ID?

I have a big problem.

A friend of mine has a new nintendo 3ds. Because its old 3ds, the display no longer shows anything. Now he wants to have his data from his old nintendo on the new nintendo. Problem: The touchscreen is responding. But you don't see anything anymore. Transfer not possible. How can I unsubscribe from the accaunt?

As far as I know, this is only possible with the 3DS. You could try to delete the account via the Nintendo website, that should work. You also get a confirmation email when you create the network ID. Otherwise if you still have a look there, there may be a link to delete the ID.

My friend does not want to delete the ID but want his old games on the new nintendo.

This can only be done by data transfer, if the old DS is broken it won't work. Unless he has approved the ID for multiple devices. Then you have to register the ID from the old device to the new one and then the games should be back