Hmmm, you probably need to work out why these particular stories are sticking in your head, to make them go? Do you have issues with your mother (or her death)? Or are you worried about how your kids will cope when you die?
Oh, yes, of course it's normal, should have said! But I'd use the fact these things are sticking in your head as a clue that something's going on, subconsciously, that you maybe need to have a think about.
It's hard when they're death-obsessed, isn't it? My DS1 was for a while, and that coincided, a bit, with my mother's death, so we had to keep talking about what had happened with her ashes, and how she was dead now, and how I missed her.