Thank you and sorry you had to go through all that. Luckily I was able to get in and delete the account. I've had multiple experiences with older relatives losing their accounts as well. It's tough to help them with security when they have trouble even navigating the app/browser let alone figuring out how to use an authenticator app. I've tried to get them cheap tablets or chromebooks to use specifically for their social media then keep their other computers just for email/taxes and that seems to have helped, but still not ideal.
And yes using an authenticator app is my big takeaway here too. I was lazy and delayed migrating all my accounts over to it, but this has definitely spurred some action on that front.