Locked Apple ID !AND! Device (iPhone 6s Plus)

Hi,

Background on the situation:

My Brother lost his Samsung, so until his contract renewed in a few months I gave him my old iPhone 6s Plus. He created his Apple ID and setup up the device, all was fine. Stupidly he either forgot or repeatedly entered the incorrect password in for his Apple ID and had his account locked. And on top of that forgot the pin to the iPhone. So then he could not reset his device without his Apple ID and could not reset his Apple ID without the device.

What I have attempted:

So then I attempted to reset his password of his Apple ID as the only sensible thing he had done is enter my telephone number as his main number for his Apple ID as he couldn't remember his own. I was sent the code and entered it, thus far confirming my ID. (Normally this would be sufficient to reset a password, but oh no Apple this isnt good enough) I get a message saying:

"We are evaluating your information to determine when you will be able to reset your password.

We will contact you within the next 24 hours at ***********@gmail.com to let you know when you will be able to reset your password."

So that I follow the link below this message to see the status of my request only to be faced with:

You will be able to reset your password in 13 days.

2 Weeks to be able to gain access to the account is out of order.

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On top of that I have tried to Restore the iPhone using a Fully Up to date iTunes and up to date operating system. But for love nor ****** money can I accomplish this either.

I just persistently get the message "The iPhone could not be restored. An UNKNOWN ERROR has occured (3600) after going the "Update & Restore" route.

I have triple checked my security setting as recommended also.

So as you can see I am very frustrated with the lack of support and accessibility on this. What do you's, in your infinite wisdom suggest I attempt next?