DH is the first to admit he is not very techy - and tbf he doesn't need to be. At work his computer issues are looked after by IT, and at home I set stuff up and tear my hair out do my best to fix IT issues with the help of Google. He has a PC at work, and an ancient tablet at home which he does all his social media and browsing on, and although he inherited an old smartphone of DD's, doesn't do much on it.
Yesterday the tablet died (got dropped and nothing on the screen is visible) and I set him up on the family iPad for his social media, but he can't get into his emails. He can't remember his password (he's been using the same account and device for years and cookies have remembered the password for him). He hasn't got his phone set up as back up security and doesn't think he's ever used the phone to access emails, so the device isn't being recognised as his and codes sent to phone aren't being accepted as proof of ID. No security questions were offered by gmail as an alternative and I can't see a way to prompt them. I've tried sending the verification code to another gmail account of his but it looks like those accounts aren't linked either. 
We're now at loggerheads because he accepts that he should have these backups set up and his password written down somewhere safe but none of this is helping him retrieve the account. I'm struggling to think of anything else to try though. The gmail help page suggests setting up a new account which isn't really much of a solution!
The only possible solution I can think of is to use his work email to verify the account - but he is currently furloughed and can't access his work email without getting permission from his company to go in to the office - I'm also not sure if gmail locks you out permanently after a certain number of unsuccessful attempts - so if anyone has any other suggestions to try first I'd love to hear them!
And if you've got this far thank you for your patience and make sure you have set up your security backups on your accounts in case of disaster!