Do I need to empty it out before putting it for sale?
That depends on how you plan to sell the house. But at the very least you’ll probably want to remove personal effects from the house, like clothes, pictures, jewelry, etc. You might be able to list the house as FSBO with the old furniture still there, but it will be a hard sell if personal items belonging to the person who just passed away are still there.
If you plan on using an agent, I don’t know how insistent they are on having the house emptied out. That’ll depend on the agent you choose to work with, I suppose. But a good agent should be able to get you in touch with people who can clear out the house for you, so you won’t have to drive there to take care of it.
Another alternative is to sell the house to a home buying company. This is a popular option among those looking to sell a house fast in Southern California because — as this website shows — such companies buy homes as-is. Meaning you won’t have to empty it out or make any repairs.