My condolences to the family as well.
A reporter from MSNBC is speaking with some of the pax from that flight. He is reporting that the pax were not notified that the captain had died, but that the crew did ask for the assistance of any medical personnel on board. Also, many of the pax said that although they're learning of the events now from the media, they're okay that they weren't notified on board because it probably would have caused quite a panic.