The prior answers provided good info.
But, I assume you are worried about whether you can stay in the home & what rent you would be required to pay if the home is not listed for sale. My suggestion is first ask your mom or dad, whichever one whose dad passed away, what is happening with the home. If your mom or dad has passed away, ask an aunt or uncle. Another suggestion is to contact the Probate Court to find out who is the Executor/Administrator of your grandfather's estate, so you can talk to them. Many times the Executor/Administrator is a family member or a close friend, but sometimes it is an attorney.
Here is a web site that might help you with understanding more about the probate process:
You might also contact the Santa Clara Public Administrator to see if you qualify for legal assistance in handling the matter. (408) 577-2500