Apple ID Issue

[Lindaelaine]

My husband is getting notifications to update his Apple ID settings, problem is the Apple notification, comes up with a really old email address he used to have with Yahoo, although he puts the correct password in it isn't recognised. we tried to access the old yahoo mail and and the email address no longer exists.

He hasn't needed to sign into Apple for years and he is able to use his phone, it's just annoying that the notification pops up, the notification is also in settings under his profile.

Would there be a problem if he just created a new Apple ID? I realise he would have to sign out of his Apple ID to do this and have no idea what the consequences would be, it sounds like a silly question but would his apps still be on his phone if he created a new account? I cannot see any other way round it as even if he had to have his phone restored he would still not be able to sign in to his old Apple ID 🤷

Seeing as he hasn't needed to sign in it for years he could just leave things as they are with the notification still popping up but if he needed to get a new phone it could cause problems ?
Thanks in advance and any advice appreciated .