how can i ask for us to keep the house?

My grandmother passed away a year ago, my grandpa this December. He had 3 daughters, i'm one of his granddaughters, and the house is supposed to be sold and the profit split up in thirds.

my grandparents always took care of my aunts, but never my mom. the aunts had their mortgages basically paid off, they paid for their vacations when we'd all go as a family-- the biggest expense was helping pay for me and my sibling's college.

one of my aunts came in a few months before the end, furious that we wanted POA because she thought we were trying to steal his money. she backed down, but she's also done stuff like taking heirlooms without asking.

the way my mom tells it, they kind of split up the estate in their heads for a while now.

my parents took care of him through his old age, even when he was screaming and confused. they drove him, took care of his groceries, bathed him, they were basically full-time care until they had POA.

the thing is, his house has always been a block away from mine. i went over at least once a week, we were supposed to be left the house, but he developed dementia before he could change his will to reflect this. i want the house. i really, really want the house. he has some valuable things, but on the whole i don't care of those get sold. even the valuable things with sentimental value to me i don't mind giving up if it means i can keep his kitchen & garden.

i guess i just don't know where to start, or how to start asking. any advice?