Something I feel like you've left out that is important: It's a gesture of respect, ensuring that no one's passing goes unnoticed.

And more of a comment to the other replies; a relative being unable to be contacted currently doesn't mean they don't care. Them finding out later and knowing, despite everything, they got a dignified ending might give them some peace. These funerals are not being held for the people attending them but at the same time you can't have a funeral without someone attending them.