How to Retrieve Apple ID PW if You Don't Have the Associated Cell Phone

Guys I know this is a long way from being an Apple support forum, but I don't know Apple forums, and there are some clever Apple users here.  Fingers crossed.

The elderly gentleman next door to my mother-in-law (where we are currently staying) has forgotten the password for his Apple ID.  To make life difficult, he no longer has access to the cell phone associated with his Apple ID, and after searching for ages, I can't find a way to get the password sent to his email address.  That email address is also his Apple ID.

He is trying to get on to his iPad, but he has no idea what model it is, so we don't know what version of IOS.  He certainly doesn't know his verification code, but he might know the answers to security questions.  Is this doble. or does he need to contact Apple support?  He has a working laptop that he can access his email on.

The poor guy has had a stroke, and is pretty messed up, so we'd like to help him.    I can PM his Apple ID / email address to anyone who can help.

Otherwise,  if you can advise the go-to Apple forum, that would be good.

Thanks guys.