well, I guess he didn't like my first response which was to have some respect. Seriously, she just passed. I would think the first thing one would think of would be; what do we do with grandma. Not; what do we do with grandma's estate.
But once OP settles down:
if they live to where they can visit the area of grandma's house easily, they should contact the police to be sure they are finished with their investigation. Then they should secure the home. (cops have been known to leave a home unlocked).
Then OP can start investigating the situation. Was grandma ever married? If so, what happened to the spouse?