Post office bank accounts and brexit

A friend of mine with a holiday home in Italy would like to close his Italian bank account and open a Post office account instead as the charges seem a lot less. When he enquired about this the other week, despite going to the Post office 3 times and visiting other Post offices to enquire, he was told this was not possible unless he had an Italian identity card and it seemed to be something to do with Brexit although we are still in the EU at the moment. He was managing with limited Italian and limited English by the staff, so he is not sure if he understood properly, but he does know he was not allowed to open an account there.
Can anyone throw any light on this? I’ve thought about changing to a Post Office account myself but may have left it too late.
I’d be grateful for any information on this.

We've banked with the post office for several years now and can't remember if we needed our Carta D'Identita but we have one so perhaps yes. Just renewed our identity cards for another 10 years. Can recommend the PO good, reliable service.

Another friend opened an account easily without a carta d’identita  2or 3 years ago. I don’t think any of us qualify for one as only in Italy for holidays. I wish I’d got round to changing earlier.

In theory, it is possible to open a bank account for on residents using your passport. It does not have the same fees and charges of an ordinary account. 
https://www.bancheitalia.it/conti-correnti/conto-corrente-postale.htm
Now, whether the Post Office is reluctant to open an account not knowing what is going to happen after Brexit is a different matter. After all it is the bank’s decision whether they open an account or reject it.

I just hope the banks we are already using don’t decide to eject us after Brexit!