Welcome to Just Answer.
People who don't seem to have much of an awareness of other people, their feelings, or experiences, are sometimes just young - emotionally immature. WHen that's taken to an extreme, it can be a defense mechanism - sort of a denial of other people and self- focus. It takes on narcissistic traits.
Chances are, no matter what you say or do, she is not going to really get it - she does this to not see what's going on in her life - it's a defense mechanism.
If you do "confront" her on her thoughts and behaviors, you risk losing her friendship - so my suggestion is to just either put up with it, or gently remind her now and again that it would be nice if she talked about other things, or had other concerns - like you, or other issues in the world.
Some people take longer to grow up and part of growing up is being able to see outside ourselves - it just sounds like she isn't there yet... but we all do grow up eventually and sometimes need little gentle, loving pushes in the right direction.
You've been a good friend for many years - help her to grow up :-)