Some grandparents still talk about someone they lost sixty years ago. Love doesn’t really expire. It just changes rooms.

Attachment does not have a shelf life. Somebody can be gone for decades and still be present in how a person talks, what they cook, the stories they keep returning to. That is not a failure to move on, it is what happens when a relationship was real.

If an older relative mentions somebody you never met, you could ask about them instead of changing the subject. Most people want to talk about them and assume nobody wants to hear it.