It might have something to do with the new managed payments system that came into effect a few weeks ago - payments are now processed through Adyen, and Paypal has been removed from the equation. As part of the new requirements for sellers, they have had to identify themselves by uploading certain ID docs such as a passport or drivers licence and all payments are now sent to a bank account. I'm not sure if you would have had to go through that process yet as it is still being rolled out and you may have been able to register under the old requirements.

As part of this overhaul, the listing of coins is no longer permitted.

It's also possible that your dad's old account had a balance owing and that needs to be resolved.