Apple

So I tried signing into my mother‘s older Apple ID and I’ve entered in her password correctly, but it needs trusted phone number but that’s the huge huge ass problem. She died and she created a recovery key for some stupid reason. Have fun hours have been deactivated, and I have no way of getting in to the account without the recovery key, which I don’t know. And even get to wear masks for the recovery key number which won’t work because those numbers have been deactivated. What do I do? How do I get into that old account?