Erasing iCloud id

My brothers partner has passed away. He has very kindly given me her phone. He has removed the SIM card (and cut it up) but it is still connected to her iCloud account.

The phone is working with my sim in it but I can’t get a text with the verification code to allow me to change the password so I can delete her iCloud. I got an email sent to her account but I just get an error code. What can I do please?