My aunt and cousins keep walking around my grandparents house calling “dibs.” (Not in front of me)

THEY ARE ASS HOLES
WHO EVER PICKED ANY OTHER RESPONSE YOU AGREE WITH THEY BEHAVIOR. YOU'RE A VILE PERSON

You're not sensitive and it is kinda a big deal. That's something horrible to do it's like your counting down their days. If i were you i would have them at up a living will

Was this started by your grandparents? Did they say something like...let me know what you want when we die?
Both of my parents have done this already and they are both in relatively good health.

my friends grandma (years before she passed) literally had her grandkids/kids stick post-it notes on things that they wanted when she passed on. her whole house was covered😂my family hasn’t gone to that extreme, but my perfectly healthy parents have already asked me and my brother what we would like too.
It is quite common for families to do these kinda things, or at least speak about it. If this isn’t normal in your family tho, and the grandparents don’t like it either, then yes it’s disrespectful. It’s still a sensitive topic either way tho, so don’t think you’re being dramatic. no one likes situations like these and it’s always gonna be upsetting x