How does Facebook deal with death? 

What will happen to my Facebook account when I pass away?
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Facebook has the option where you can set in advance whether you’d like to have your account memorialized or permanently deleted after you pass away. A memorialized account is a place for your friends and family to visit and share memories after a person has passed away.

And since last year, Facebook now allows you to designate a “legacy contact” to manage your account.  Once your account is memorialized, this person can post on your timeline after your death, such as share a final message.  Other things he or she can do:

1. Post on your timeline (ex. memorial service information)
2. Respond to new friend requests (ex. friends or family who weren’t Facebook users yet)
3. Update your cover photo and profile picture
4. Download an archive of what you have shared on Facebook (ex. photos/videos, wall posts, profile and contact info, events and friends list).

Your legacy contact currently is not able to:

1. Log into your account
2. Remove or change previous posts or pictures
3. Read your private messages
4. Remove any of your friends.

If you want to designate your legacy contact:

1. Go to your “Settings” page
2. Click on “Security” in the upper left hand corner
3. Click on “Legacy Contact”
4. Choose one of your Facebook friends as your legacy contact.

Reference: https://www.facebook.com/help/1568013990080948